The Collaborative International Dictionary of English v.0.48:

Unpeaceful \Unpeaceful\
   See peaceful.

WordNet (r) 3.0 (2006):

unpeaceful
    adj 1: not peaceful; "unpeaceful times"; "an unpeaceful
           marriage" [ant: peaceable, peaceful]

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "unpeaceful":
   aggressive, agitated, antagonistic, battling, bellicose,
   belligerent, bloodthirsty, bloody, bloody-minded, chauvinist,
   chauvinistic, combative, contentious, discomposed, disquieted,
   disturbed, enemy, excited, ferocious, feverish, fidgety, fierce,
   fighting, flurried, flustered, full of fight, hawkish, hostile,
   inimical, jingo, jingoish, jingoist, jingoistic, jittery, jumpy,
   martial, militant, militaristic, military, nervous, nervy,
   offensive, perturbed, pugnacious, quarrelsome, restless, ruffled,
   saber-rattling, sanguinary, sanguineous, savage, scrappy, shaken,
   shaken up, soldierlike, soldierly, stirred up, trigger-happy,
   troubled, troublous, truculent, turbulent, uneasy, unfriendly,
   unpacific, unpeaceable, unquiet, unrestful, unsettled, upset,
   warlike, warmongering, warring