You might be thinking of kapp or kappa, the twitch emotes used to call someone's bluff or accuse them of lying
Dumbass: "Yah dude and I was the best player they had. No one could beat me" Me: "kapp (cap), you were not" or simply "kapp"
by guest_2 December 7, 2019

A conversation between Capcom fans
OP: “I like Resident Evil 8, it’s actually pretty good!”
Reply: “Preposterous! Nothing will ever beat Resident Evil 4!”
OP: “Oh lord, it’s a Cap-cunt.”
OP: “I like Resident Evil 8, it’s actually pretty good!”
Reply: “Preposterous! Nothing will ever beat Resident Evil 4!”
OP: “Oh lord, it’s a Cap-cunt.”
by ninuno January 24, 2023

(noun) the top of a bottle or can usually supposed to be screwed off
(verb) to say something is wrong; hitting your head with your hand up & down signaling that is "cap" which is also known as "capping"
(verb) to say something is wrong; hitting your head with your hand up & down signaling that is "cap" which is also known as "capping"
by URDADGOTDAMILKIDIOT October 3, 2023

by Pedro Huncho March 10, 2019

The act of placing one's oral cavity within near proximity of his/her patellas. Generally a move indicative of inherent flexibility and/or the absence of two or more ribs.
Did you see that flexible prick Marilyn Manson got busted lippin' caps in a public washroom in Dallas?
by Robhouse November 25, 2013

one definition for the word cap is to shoot someone but most people
know it as the more current definitions which basically means that someone is lying so technically just a synonym for lying or a lie
know it as the more current definitions which basically means that someone is lying so technically just a synonym for lying or a lie
jimmy: bro imma cap you if you don’t stfu
chris: alright jimmy calm down
or
jimmy: ayo chris david told me you were going on vacation to hawaii with everyone but didn’t invite me
chris: that’s cap i would never do that
chris: alright jimmy calm down
or
jimmy: ayo chris david told me you were going on vacation to hawaii with everyone but didn’t invite me
chris: that’s cap i would never do that
by immagenius1115 April 21, 2021

When you don't capitalize letters in text in order to obfuscate one's commitment to their statement,
by Miggum September 28, 2019
