1. incapable of being justified or explained (Freq. 1) • Syn: indefensible, insupportable, unjustifiable, unwarrantable • Similar to: inexcusable 2. without a basis in reason or fact - baseless gossip - the allegations proved groundless - idle fears - unfounded suspicions - unwarranted jealousy • Syn: baseless, groundless, idle, unfounded, wild • Similar to: unsupported • Derivationally related forms: idleness (for: idle) 3. lacking justification or authorization - desire for undue private profit - unwarranted limitations of personal freedom • Syn: undue, unjustified • Similar to: unreasonable