nana (1)EnglishOxford New American Dictionarynana1 /ˈnanə, ˈnænə / ▸ noun British informal a silly person; a fool (often as a general term of abuse): I was made to look a right nana. – PHRASES off one's nana Australian New Zealand informal mad or crazy: he's absolutely gone off his nana.– ORIGIN 1960s : perhaps a shortening of banana.