FLAK Meaning of FLAK in English [flak] n, pl flak [G, fr. Fliegerabwehrkanonen, fr. Flieger flyer + Abwehr defense + Kanonen cannons] (1938) 1: antiaircraft guns 2: the bursting shells fired from flak 3: criticism, opposition Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012