Adj. An abbreviation of the classifieds/sales term "Or best offer". Used in the
context of describing a man or woman who will take
whatever he/she can get in the way of
romantic companionship.
Melissa? She's a
drunk with a lot of mileage on her. She's truly OBO.
Adam has slept with all of his friends'
ex-girlfriends and now he's been hanging around that
creepy, snaggletoothed, bettie page impersonator's house. Isn't she almost 50? Officially OBO.