immorally β violating moral principles; not conforming to the patterns of conduct usually accepted or established as consistent with principles of personal and social ethics.
maliciously β full of, characterized by, or showing malice; intentionally harmful; spiteful: malicious gossip.
basely β morally low; without estimable personal qualities; dishonorable; meanspirited; selfish; cowardly.
behind one's back β without one's knowledge; secretly or deceitfully
crookedly β not straight; bending; curved: a crooked path.
dishonorable β showing lack of honor or integrity; ignoble; base; disgraceful; shameful: Cheating is dishonorable.
disloyal β false to one's obligations or allegiances; not loyal; faithless; treacherous.
faithless β not adhering to allegiance, promises, vows, or duty: the faithless behavior of Benedict Arnold.
malevolently β wishing evil or harm to another or others; showing ill will; ill-disposed; malicious: His failures made him malevolent toward those who were successful.
perfidiously β deliberately faithless; treacherous; deceitful: a perfidious lover.
roguishly β pertaining to, characteristic of, or acting like a rogue; knavish or rascally.
traitorous β having the character of a traitor; treacherous; perfidious.
treacherously β characterized by faithlessness or readiness to betray trust; traitorous.
unfaithful β not faithful; false to duty, obligation, or promises; faithless; disloyal.
unscrupulously β not scrupulous; unrestrained by scruples; conscienceless; unprincipled.
unjustly β not just; lacking in justice or fairness: unjust criticism; an unjust ruler.
unreasonably β not reasonable or rational; acting at variance with or contrary to reason; not guided by reason or sound judgment; irrational: an unreasonable person.
below the belt β a band of flexible material, as leather or cord, for encircling the waist.