Jul 6, 2025 flunk ˈfləŋk 1 syllable uncommon ‹ verb. to fail especially in an examination or course was worried he would flunkThe teacher flunked half the class. verb. to give a failing grade to flunked the math exam verb. to get a failing grade or result in noun. an act or instance of flunking › Origin perhaps blend of flinch and funk.