sneakily Synonyms

surreptitiously without one's knowledge on the side on the quiet on the qt on the q.t. insidiously in confidence in camera secretively on the sly shiftily in a secretive way in a secretive manner in a secret in a quiet way behind back behind one's back under the counter under cover undercover discreetly deviously conspiratorially quietly privily privately intimately furtively deceitfully craftily covertly confidentially scurvily secretly collusively clandestinely behind someone's back behind closed doors backstage shrewdly underhandedly stealthily slyly cleverly