sneakily Synonyms

surreptitiously without one's knowledge on the quiet on the qt on the q.t. insidiously in confidence in camera secretively discreetly deviously on the side on the sly 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 shiftily conspiratorially collusively quietly privily privately intimately furtively deceitfully cuckoldly craftily covertly confidentially scurvily secretly clandestinely behind someone's back behind closed doors sub-rosa backstage shrewdly underhandedly stealthily slyly slily cleverly