A person who is illegitimate was born of parents who were not married to each other.
They discovered he had an illegitimate child.
他们发现他有一个私生子。
Illegitimate is used to describe activities and institutions that are not in accordance with the law or with accepted standards of what is right.
He realized that, otherwise, the election would have been dismissed as illegitimate by the international community.
他意识到,若非这样,国际社会就会以非法为由而不承认选举结果。