For cool people: the mischievous act of fooling one person or more to deliver a punchline in a way that is funny for everyone.
For jackasses: straight up bullying, spamming, conning with no punchline, some form of trauma dumping, breaking people's stuff, and more.
Dear god i miss when trolling was actually funny.
"Man, remember when trolled you by keeping taking stuff out of your room till you noticed?" - Cliche trolling.
"Let's troll Peter by surrounding his afk ass in these scarecrow NPCs." - Another example, still cliche trolling.
"I kept ordering pizzas to this guy house till he was blacklisted from all pizzerias. We do a little trolling." - Jackass trolling.
"I kept trolling this insert derogatory therm by spamming him with insert side of the political spectrum propaganda. He's so mad." - Another example of jackass trolling.