Definition from Wiktionary, the free dictionary
forro m (plural forros)
- dust jacket
- (heraldry) fur
- (Argentina) (condom): raincoat, glove
- (Argentina) said to refer to people that are obnoxious, sometimes treacherous. Full expression "Forro pinchado" ("Perforated condom") - as being the result of, hence the treacherous/obnoxious meaning.