A white, ribbed, sleevless tee-shirt. Known also as a wife-beater singlet or a muscle shirt. Worn primarily as an undershirt, as its name implies, generally worn as a normal shirt on any given day by Itallian-Americans (Guineas, or the New Jersey sub-species of 'guidos') from Brooklyn, hence the name; "Guinea Tee". Usually found in its natural habitat along coexistant species such as the baseball bat, Mets hats, and copius amounts of hair gel.
Ey, yo, Luca, wassamattuh wichoo, uh? You just spilled beer on my guinea tee. Ahhh....fuggetaboudit.