underhandedly Synonyms

underhand confidentially clandestinely untruthfully unfairly underhanded stealthily slyly slily deviously dishonorably treacherously sneakily shiftily on the sly on the quiet insidiously in camera surreptitiously shadily secretly disloyally dishonestly deceptively deceitfully crookedly craftily covertly corruptly falsely fraudulently quietly privately overly intimately insincerely infamously immorally furtively unscrupulously