jump in

verb

Etymology: For the US slang sense, compare jump (“attack suddenly and violently”).

1. To enter something quickly, usually a mode of transport.

   “I jumped in the car, and we sped off to the meeting.”

2. To join in on an activity quickly.
3. To interrupt someone while they are speaking.
4. To initiate into an organization, usually a gang, with violence.

   “[Toothpick:] Been hanging with the homies in the hood for a while now / [Al Dog:] 'Bout time we jump your punk ass in / [Toothpick:] That's right. Let me tell you something in this world if you can't swim / [Al Dog:] You bound to drizzown / [Toothpick:] Yeah, and if you fall you better pick your punk ass up / [Al Dog:] That's right / [Toothpick, turning to the rest of the gang:] And the rest of y'all don't cut him no slack. Y'all fools get busy [they precede to a game of jump rope with the young man Toothpick and Al Dog were talking to jumping]”

   “His [my cousin's] uncle was already in the gang. […] So, we go up to the guys, we didn't even know how to ask, kinda like "Hey, uh, can we get jumped in?" And they're like, "Yeah, come on." And all I remember is I landed on the ground and he [one of the gang members] got on top of me and boom! I blanked out.”

5. To play a card that matches the top card in the discard pile out of turn.

   “With +2, you build on them /add them together in a similar way, but you can only jump in if you have the same color +2, OR if the player whose turn it is has a +2 of any color, he can play it, since it is his turn and he is not jumping in on anyone. […] The wilds can be jumped in on by any wild.”

6. Used other than figuratively or idiomatically: see jump, in.

   “Cathy led the pig down to the pen. “Don’t jump in the mud,” she said. But a pig is a pig. It jumped in the mud.”

   “From the way you skip and jump in the air when excited.”

7. To ambush (someone).