Synonyms of immoral in English:

unethical, bad, morally wrong, wrongful, wicked, evil, unprincipled, unscrupulous, dishonourable, dishonest, unconscionable, iniquitous, disreputable, fraudulent, corrupt, depraved, vile, villainous, nefarious, base, unfair, underhand, devious

sinful, impure, unchaste, unvirtuous, shameless, degenerate, debauched, abandoned, dissolute, reprobate, perverted, indecent, lewd, licentious, wanton, bawdy, lustful, promiscuous, whorish

informal shady, low-down

British informal dodgy, crooked, not cricket

archaic miscreant