gentlemanly adjective 1adverb 1forms 4 adjective1 •Of, being, pertaining to, or resembling a gentleman or gentlemen.Some schools bump up everyone’s grades, some just allow for more As and others all but eliminate the once-gentlemanly C. — 2010 adverb1 •In the manner or with the behavior of a gentleman; with social grace, politely.He went gentlemanly dressed in East Virginia style, wore a high-top silk hat, as had lawyer Park, and sported a gold headed walking cane. — 1938 formsgentlemanlier · more gentlemanly · gentlemanliest · most gentlemanly