TOEFL dumbfound Definition to astonish or bewilder someone greatly. Example "The magician's final trick completely dumbfounded the audience." Sign in to save TOEFL PDF — $25 ← dumb dump → Study tips featuring "dumbfound" TOEFL Academic Vocabulary: Study by Topic Related words TOEFL brighten GRE abash GRE abate GRE abbreviate GRE abbreviation SAT abdicate GRE abduct SAT abet GRE abhor GRE abide SAT abject TOEFL ablaze