When a girl is wearing large, men t-shirts that do not fit her, while going out in public or to a party.
Its Friday night and your at a party looking for that fine girl. Your friend comes up to you and points out the weird nasty girl. You ask who and he says the one (macked out).
We totally macked out that 'whatever', showing it taken over-the-top...like a kitchen loaded with top-of-the-line appliances, PLUS some other cool stuff.