Illegitimate a. : Not according to law; not regular or authorized; unlawful; improper.

Illegitimate a. : Unlawfully begotten; born out of wedlock; bastard; as, an illegitimate child.

Illegitimate a. : Not legitimately deduced or inferred; illogical; as, an illegitimate inference.

Illegitimate a. : Not authorized by good usage; not genuine; spurious; as, an illegitimate word.

Illegitimate v. t. : To render illegitimate; to declare or prove to be born out of wedlock; to bastardize; to illegitimatize.

Example:
What were Eighteenth Century punishments for having Illegitimate children and why?

Taxonomy
Legitimacy, illegitimacy, parents, marriage, illegitimate, births, illegitimate children, United States, law, History, free encyclopedia, legally, wedlock, unwed mothers, out-of-wedlock births, Europe, one another, common-law.

Defination from the web:
illegitimate children in the Russian Empire. History, indeed, shows striking examples of prominent persons of illegitimate birth who have been driven to excel in their fields of endeavor in ...