The Collaborative International Dictionary of English v.0.48:
Unjust \Un*just"\, a.
1. Acting contrary to the standard of right; not animated or
controlled by justice; false; dishonest; as, an unjust man
2. Contrary to justice and right; prompted by a spirit of
injustice; wrongful; as, an unjust sentence; an unjust
demand; an unjust accusation.
[1913 Webster] -- Un*just"ly, adv. -- Un*just"ness, n.
Bouvier's Law Dictionary, Revised 6th Ed (1856):
UNJUST. That which is done against the perfect rights of another; that which
is against the established law; that which is opposed to a law which is the
test of right and wrong. 1 Toull. tit. prel. n. 5; Aust. Jur. 276, n.; Hein.
Lec. El. Sec. 1080.