Does exactly what it says on the tin
: A boy
trying to be a lady
(although I think "Lady" may be an inappropriate term given the circumstances...)
Probably most notorious for their abundance in Thailand, the ladyboys have often undergone some form of hormonal programme to give them breasts; are usually tarted up and shaven; and have mastered the art of the female sexy-walk. Are commonly found hanging around bars, waiting to be picked up by drunk Westerners who can't tell the difference...
...until they get them round the corner into a dark alley - cue fumbling, confusion, realisation, shock, then the overwhelming urge to puke, run away, and never tell your mates of the experience. Unless you're into that sort of thing, in which case you're making the most of it.
Not to be confused with ladybirds, which don't live in Thailand, and lead nowhere near as exciting a life.