accidentally upvoting a post on yik yak that you meant to downvote (and vice versa). Yakcidents suck because you can't undo a yakcident. Also used as yakcidental and yakcidentally.
Ahhh shit man, I yakcidentally downvoted my own yak!
A road traffic accident, prodomently occuring in the UK, involving Women Pakis (Wakis) who are uninsured and covered by a blanket Community Licence. They generally can't see over the steering wheel of their vehicle and almost always are wearing Burkahs at the time of the Wakcident. After the Wakcident there is very little exchange of English. The Waki is always at fault.