DUMBO Meaning of DUMBO in English /dum"boh/ , n. , pl. dumbos , adj. Slang.n.1. a stupid person: a class full of dumbos.adj.2. stupid or foolish: What a dumbo idea![ ‡1955-60; DUMB + -O ] Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012