While everyone is giving you good advice about how to be yourself and how to deal with jerks, I am going to take a different approach and simply answer your question.

In order to have wit you have to have two things: an understanding of humor and thick skin.

Understanding humor means being able to break apart the message and find a way to reinterpret it in a relevant but unexpected way. The surprise is the key to a good joke, but it has to make sense. Humor exposes a truth, thus, an intentionally funny person must be able to see the truth in the world and in themselves.

Humor is a tool that takes the form of what you need. It can be a weapon, to insult or make foolish, a shield that repels, a cloak to hide your feelings or intentions, a clown nose to make another laugh, and so on.

The best way to learn humor is by listening to funny people. Watch a lot of stand-up comedians. Not only will it make your day brighter but you will absorb the essence of humor. Watch comedians that work the crowd. See how they get people to interact with them, how they handle hecklers. Even when they are under extreme pressure by performing in front of an audience, they always seem to be in control of themselves. That's how you need to be.

The second part is just as important as the first. You have to have thick skin. You can't take things personally. Humor and wit comes from a special mental place. Being too angry or hurt will prevent you from accessing this type of witty thinking. It requires a bit of cool confidence, in that even if everything else about you is lousy, you know you have the power of communication to protect or devastate at your fingertips.

To be able to clap back at someone quickly means brushing off what they say, analyzing the statement to find how to turn it around in an unexpected way, and then deliver it, not with hot anger, but with a cool, calculated malice. Slip the verbal knife between their ribs with a practiced ease and a smirk.

Do this enough and you'll get faster and faster. Pretty soon you're not even thinking on a conscious level. It only takes milliseconds to react, like a gunslinger.

Match the level. An eye for an eye. If someone is giving you a good natured poke, you can play along with them and take the 'abuse' in a funny way, or you can zing one back at them. Or even deflect it with a humorous meta comment.

If they are testing you, increase the pressure.

If they are mean spirited, go for the jugular.

You have to keep your feelings in check to respond at an appropriate level.

Being funny is a skill. But it's one that is hard to learn by thinking about it. You see it in action and you have to practice it.

Read famous insults by kings, stars, world leaders, etc. A lot of public facing people were very funny when the time was right, and had to be because they faced constant criticism.

Read classic humorous essays. Watch entertaining people tell a story. Try some jokes out in the mirror. Make a funny observation about something or someone to a friend. Don't be afraid to look foolish, once you've embarrassed yourself enough trying to make people laugh, no insult in the world can affect you.

Hope this helps.

Source: Me, a resplendent fool

Have you considered sneaking up behind them and hitting them in the head with a brick?

Memorize the comebacks you like, and workshop new ones.

But also...witty comebacks aren't as helpful as you think. Like they very rarely deescalate situations or even indicate that the other person is being rude.

Like I typically use witty comebacks when I'm either trying to be silly, or I'm serious but I've given up on the person I'm talking to and I just want to make them look foolish for everyone else (which is rare).

whenever I do some message, they reply me with messages that have that sarcasm that look funny and insulting and I don't have any comebacks for them.

Say "Hey I think you're being super rude and I don't know what I did to deserve that." No comebacks needed. If they don't respond constructively, then literally just tell them to fuck off and disengage. You don't have to tolerate people stepping on you.

Don't.

Remove people who regularly insult you ("haha, it was just a joke, can't you take anything?) from your life. They will suck your soul out in the long run. If you can't avoid dealing with them keep it very formal.

You can prepare a few stock answers for them (to repeat whenever you need them), something like "That was disrespectful, please stop it". (In your own words) You also might want to read up on setting and enforcing boundaries and red lines.

To train your spontaneity try improv workshops, but that's something you do with people whom you feel safe with, who do respect you.

You are not the only one whom they use as the butt of their jokes, so just hang around with people who are better for you. People who are making hurtful "jokes" are simply disrespectful. You can't change that by lowering yourself to their level and bitching back.

And build your creativity having fun, not fighting back. The idiots are not worthy of your time, of what you think, of what you do.

Witty comebacks are better for playful banter. You seem to be getting straight up bullied

Prepare templates in advance. Maintain an unhealthy obsession with preemptively mapping all possible conversation paths.

My 2 cents on this: it doesn't really matter. Are these people that are important in your life? If not you can just say "if that's your opinion". Even if you get the world's greatest comeback, you will only use your time and energy on people that probably don't matter and you probably won't stop people from having an opinion. You can't control how people will react to you, but you can control how you respond. Don't waste your life trying to justify yourself to others

I mean, the real answer to your problem is not to engage; not to feed the trolls. They get more reactions because they don't care about what's being said, just that they can bait you into replying. In this case, the best comeback is silence.

If I wanted my comeback, I would have wiped it off your mother's face.

Read more. Read funny, quick-witted works. Get that stockpile of phrases that cut deep.

Then take an improv class. That gets you to think on your feet.

Step 1: Be bullied from a young age in school.
Step 2: Be raised by apathetic sociopathic narrcistists and have no outlet for your negative emotions at home.
Step 3: Realize that the only way to have your peace, is by standing your ground verbally.
Step 4: Walk the fine line between being insultingly witty enough without getting the shit kicked out of you.
Step 6: Be soul crushingly lonely.
Step 7: Do that for 20 years.
Step 8: Have good comebacks for any online comments people throw at you.
Step 9: ???
Step 10: Profit.

You have to be witty to have witty comebacks.

There's thing thing called L'esprit_de_l'escalier where you think of the witty response too late. The thing is, those situations tend to pop up again, and if you've practiced it in your mind, you'll be ready next time.

Also, listen to how stand-up comics deal with hecklers.

Read Douglas Adams. He has so many useful turns of phrases you can repurpose for any situation.

If all else fails, not responding at all can be incredibly powerful.

Also, not caring about changing minds and just mocking idiots is very freeing.

"Hey AI, make me a witty comeback. No EM dashes please!

two words

I'm interested in what message you're delivering to the world.

ignore them.

don't feed the trolls.

I say this with love. If you're the kind of person to ask how to be witty online I am going to suggest that you are probably going to have better luck just being your earnest self.

Don't try to pretend to be a fast talking jerk. It won't suit you, and it's not who you are. You are clearly a sensitive person who takes the words and feelings of others to heart.

Much better to build a reputation for being a kind, thoughtful person who tries their best and doesn't let others bring them down.

If you're of traditional university age and not mature students, you're all still kids. You might be of legal age and thus qualify as "mature" by some standards, but in 20 years you'll look back and realise that, yeah, you were all still basically kids.

This explains their juvenile behaviour and why it feels right that you need to retaliate and win.

Avoid these people as much as you can. Have nothing to do with them. The best revenge here is to do well with your studies and get better grades than they do. And if you don't, at least you can say you tried your best.

If they begin to attack you physically or steal things from you, the situation is different than back at school, because you can have them cautioned, thrown off the course or even arrested. As long as you have evidence.

So if you really must do something, start making a record of who said what to you and when. And don't be anywhere alone with them.

Best thing to do is ignore them as most replies are going to add fuel to the fire, because it's likely your reaction that they're entertained by.

Wit, however, is a skill like anything, and actually delivering a sick burn on the spot when it counts is hard, and takes time to be good at. (Timing and delivery are key, if you waver at all, even a good retort will flop)

What I would say is just continue being yourself and don't let the haters get you down, because it sounds to me like maybe you're focusing on the right things at school, and maybe they're not.

With a good attitude, a clear conscience and your head held high, you'll always come out better off than them in the long run.

Live in the UK for a few years. They are vicious and hilarious. Some cultures can't take them, but it's deep in their culture.

Just send them the one frame from the meme of the guy giving the really big thumbs up. Not in the group chat, direct to them. Never ever mention to anyone else that you do this.

My friend is great at witty banter. His secret is he’s smarter than me. Sharp as a tack

(you don't have to be witty when you want to be savage.)

They don't seem to be nice people, so I wouldn't recomment to try being friends with them. If they bother you and you want to change it then speak up that they are out of line, but do so at your own accord, not because someone told you to, because you need to assess the situation. If they are reasonable then they might just not realise they are out of line, if they actually want to insult you then then it might just fuel the flames. I'd write something like "stop bothering me"