(adv.) In a secret or concealed manner; invisibly.

antagonistically apathetically chillily cold-bloodedly coldheartedly coolly deadpan dispassionately dormantly dully frostily halfheartedly heartlessly heavily hostilely impassively in cold blood inactively indifferently inertly inimically languidly languorously latently lifelessly lukewarmly passively perfunctorily phlegmatically sluggishly spiritlessly stagnantly statically stoically stolidly torpidly unamiably unamicably uncordially unemotionally unfeelingly ungenially unpassionately with dry eyes with indifference with utter indifference