A transvestite grenade. It is the moment when you realize, usually while extremely drunk and/or stoned, that the extremely hot chick you've been grinding all night on the dance floor is a transvestite.
The term was first coined on an episode of Jersey Shore when The Situation fell for one.
Dude is so smashed that he's missing all the clues that he's working a tran-ade!
A "Tranade" is a transexual or trans-gender "grenade"(see grenade)
A- Dude look at that grenade ova thurrr!haha she's nas-ty!
B- Bro, look at that bulge.... she's not only a grenade, she...or he rather, is a TRANADE.