n. 25B6; adjective
illegitimate share trading : ILLEGAL, unlawful, illicit, criminal, felonious; unlicensed, unauthorized, unsanctioned; prohibited, outlawed, banned, forbidden, proscribed; fraudulent, corrupt, dishonest; Law malfeasant; informal crooked, shady; Brit. informal bent, dodgy.
an illegitimate child : BORN OUT OF WEDLOCK; dated born on the wrong side of the blanket, unfathered; archaic bastard, natural, misbegotten, baseborn, nameless, spurious.
legal, lawful.