DUMBO Meaning of DUMBO in English dum ‧ bo /ˈdʌmbəʊ $ -boʊ/ BrE AmE noun ( plural dumbos ) [countable] informal [ Date: 1900-2000 ; Origin: ⇨ ↑ dumb 1 , on the model of jumbo ] someone who is stupid Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012