Synonyms for notion Found 7 synonyms across 2 meanings for “notion”. a vague idea in which some confidence is placed (noun) impressionfeelingbeliefopinion an odd or fanciful or capricious idea (noun) whimwhimsywhimsey Explore Related Words Rhymes with notionSynonyms for impressionSynonyms for feelingSynonyms for beliefSynonyms for opinionSynonyms for whim Synonym Finder | Rhyme Finder | Poetry Editor