Definition of illegitimate

• a. - Not according to law; not regular or authorized; unlawful; improper.
• a. - Unlawfully begotten; born out of wedlock; bastard; as, an illegitimate child.
• a. - Not legitimately deduced or inferred; illogical; as, an illegitimate inference.
• a. - Not authorized by good usage; not genuine; spurious; as, an illegitimate word.
• v. t. - To render illegitimate; to declare or prove to be born out of wedlock; to bastardize; to illegitimatize.