not authorized by the law; not in accordance with accepted standards or rules
defending workers against illegitimate managerial practices
an illegitimate exercise of power by the military
the new powers are illegitimate
(of a child) born of parents not lawfully married to each other
Henry VIII's illegitimate son, Henry Fitzroy
he is an illegitimate descendant of a wealthy New York dynasty
a person born of parents not lawfully married to each other