UNBEKNOWN /ʌnbɪˈnəʊn/ ► audio Scrabble 18 Words With Friends 23 Definition adverb without someone's knowledge. — synonyms: unbeknownst adjective (usually used with `to') occurring or existing without the knowledge of. — synonyms: unbeknown(p), unbeknownst(p) See all 61 words you can make from UNBEKNOWN → 9-letter words Words starting with U Words ending with N ← Unscramble different letters