Definition of Monotonous: Monotonous (adjective): Dull, repetitive, and lacking in variety; unchanging and uninteresting. Synonyms: repetitive, boring, tedious, unvaried Antonyms: exciting, varied, dynamic, engaging Memory Tip: Think of “monotonous” as something that feels the same over and over again, like listening to one note being played on a piano without any change in rhythm or…