Term you use when you want to take back what you had just finished saying, normally used when you claim that someone is HOT (from a distance), but once they get closer, you realize that they're NOT... and you go, "Belay my last..."
Origin: Term used in the Navy to say "Nevermind" when you change your mind or correct yourself right after giving an order to someone.
Drake: Damn, Trey, look at that Kitten over there sitting by herself. That bitch is "Daisy Duke".
(Then she turns around and you get a better view and she turns out to be more like Patti Duke"
Drake: Oh shit, my bad. Belay my last.