Originally, a kneecap. The phrase "bust a cap" originated in Northern Ireland several years before entering urban gangsta culture, and referred to the nonlethal (but fantastically painful and disabling) practice of firing a firearm at close range into the crook of the knee. The practice served, and in some areas continues to serve, primarily as an intimidation tactic, and the victim becomes a hobbling reminder of what happens to "the enemy."
I told him I'd bust a cap in his ass, but it turns out he didn't have an asscap after all, so I let him go.
by Fiasco November 08, 2004
by jim June 24, 2003
fuck buddy your like addicted to caps
by BCBudCOQ March 05, 2010
Taken from the popular Twitch.tv phrase/emote "Kappa" which means you're joking. Was later shortened to "Cap" outside of Twitch with the phrase being picked up and popularized by influencers.
by CultureSucks April 15, 2019