secretly Synonyms

in secret on the qt in one's heart behind closed doors clandestinely inconspicuously conspiratorially discreetly secretively in private privately in one's mind nebulously sub-rosa backstage deep down at heart yourself surreptitiously in camera in confidence behind back by stealth unofficially unobtrusively unobserved under the counter under cover undercover sneakingly sneakily shiftily on the sly on the side on the quiet on the q.t. off the record unknow underhandedly underground inside inly indistinctly indefinably indecisively incognito hiddenly hazily furtively esoterically