malfeasant; wrongous; contrary to law; preterlegal; extralegal; have no standing in the law(The referendum that took place in Crimea is both irrelevant and deeply significant. Irrelevant because it has no standing in the law of the country to which it applies, and because it took place while the autonomous region was under military occupation. International bodies are unlikely to recognise its outcome: the UN security council voted by 13-1 to condemn it on Saturday, with only Russia voting against. 4uzhoj); arbitrary(arbitrary detention – незаконное содержание под стражей // CNN, 2019 Alex_Odeychuk)
anything but legitimate(He advised that he had no evidence that the claim was anything but legitimate. Val_Ships); crooked(о деятельности • a crooked business deal" – same as "illegalVal_Ships)
unlawfully(The said defendant did unlawfully, knowingly, and with intent to injure and defraud, falsely completed a written instrument, to wit: a check issued by the Oregon Department of Revenue. — Вышеназванный обвиняемый незаконно, осознанно, с умыслом причинить ущерб и совершить мошенничество, подделал письменный документ, а именно: чек, выписанный налоговым управлением штата Орегон.)
