GRE TOEFL IELTS questionable Definition Open to doubt or debate; of uncertain quality or legitimacy. Example "His motives for helping were questionable." Sign in to save GRE Quiz → TOEFL Quiz → IELTS Quiz → ← quest questionnaire → Study tips featuring "questionable" Audit Your Own Writing to Find Gaps Write GRE Words Into Your Own Sentences TOEFL Academic Vocabulary: Study by Topic Related words GRE swill GRE taper GRE testy GRE abacus SAT abase GRE abash GRE abate GRE abbreviate GRE abbreviation SAT abdicate SAT abdomen GRE abduct