term:

Illegitimate

illegitimate adj

1 : not recognized by the law as offspring
;specif
: born out of marriage NOTE: An illegitimate child is usually legitimated by his or her parents' later marriage. Illegitimate children generally have the same inheritance rights under intestate successions as legitimate children; statutes limiting their inheritance rights have been found to violate the equal protection clause.
2 : not valid according to law
illegitimate n

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.