MONOTONOUS /məˈnɒtənəs/ Scrabble 12 Words With Friends 16 Definition adjective tediously repetitious or lacking in variety. — synonyms: humdrum adjective sounded or spoken in a tone unvarying in pitch. — synonyms: flat, monotone, monotonic See all 98 words you can make from MONOTONOUS → 10-letter words Words starting with M Words ending with S ← Unscramble different letters