flatlyPronunciation: /ˈflatli/Translate flatly | into German | into Italian | into Spanish Definition of flatly adverb 1showing little interest or emotion:‘You’d better go’ she said flatly 2in a firm and unequivocal manner; absolutely:they flatly refused to play 3in a smooth and even way:I applied the paint flatly Photography without marked contrast of light and dark:the photographs were lit very flatlyflatly in other Oxford dictionaries Definition of flatly in the US English dictionary