unlawful vs. illegal

adjective

  1. not lawful; contrary to law; illegal.

    Synonyms: illicit
  2. born out of wedlock; illegitimate.

    Synonyms: natural, bastard

adjective

  1. forbidden by law or statute.

  2. contrary to or forbidden by official rules, regulations, etc..

    The referee ruled that it was an illegal forward pass.

noun

  1. Informal: Disparaging and Offensive.,  illegal alien.