Synonyms of the word

felonious

• adj. Of, relating to, being, or having the quality of felony.
• adj. (law) Done with intent to commit a crime.

criminal

• adj. Being against the law; forbidden by law.
• adj. Guilty of breaking the law.
• adj. Of or relating to crime or penal law.
• adj. (figuratively) Abhorrent or very undesirable, even if allowed by law.
• n. A person who is guilty of a crime, notably breaking the law.

illegal

• adj. Contrary to or forbidden by law, especially criminal law.
• adj. Forbidden by established rules.
• adj. (philately, of an issue printed for collectors) Totally fictitious, and often issued on behalf of a non-existent…
• adj. (of a person, sometimes offensive) Being or doing something illegally.
• adj. (chiefly US, sometimes offensive) Being an illegal immigrant; residing in a country illegally.
• n. (colloquial, offensive) An illegal immigrant.
• n. An illegal resident spy.