WordWeb Online

1. Not fair; marked by injustice, partiality or deception
   "used unjust methods";
   - unfair
    
2. Violating principles of justice
   "unjust punishment"; "an unjust judge"; "an unjust accusation"
    
3. Not equitable or fair
   "the unjust division of wealth";
   - inequitable

See also: actionable, below the belt, cheating, dirty, dishonorable [US], dishonourable [Brit, Cdn], equity, fairness, foul, partial, raw, unrighteous, unsporting, unsportsmanlike, wrong, wrongful

Antonym: just

Encyclopedia: Unjust