2 definitions by urbanwordsmith

When you extend an invite to a group of people in a room and there are people there you don't want to invite, but have to because it's the polite thing to do.
A: what the hell is he/she doing here?

B: collateral invite.

A: oh. i'm sorry.
by urbanwordsmith September 11, 2010
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Having sex with someone when you honestly didn't intend to, or are trying not to. Not always a bad thing and is no big deal because 'hey, accidents happen'.
I went over to my ex's place to drop off some stuff last night. We got talking, one thing led to another and we had accidental sex.
by urbanwordsmith June 14, 2008
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