A person who agrees to going out or some other type of plan but completely backs out at the last minute, often with a poor excuse. Hence; wigging out.
Rich: 'Are you coming into town with us tonight?'
Georgy: 'Yeah yeah I'll meet you guys there!'
...
Rich: 'Where the hell were you last night?!?'
Georgy: 'Ummm I was out, guess you just must not have seen me... I definately wasnt at my girlfriends instead.'
Rich: 'Fucking wigout.'
someone who has consumed anytype od drug, and preceeds to talk shit, or do stupid things. Paranoia is also a comon form of wigging out.
dave - "im going to batter you with my bong!"(waveing a medium sized indian hookah bong)
Wil - "what? fuckoff!"
Dave - "im tell you man im goin to fuck you up!"
Wil - "dave man your wigging out!"