The Collaborative International Dictionary of English v.0.48:

Unarmed \Unarmed\
   See armed.

The Collaborative International Dictionary of English v.0.48:

Unarmed \Un*armed"\, a. [Pref. un- not + armed.]
   1. Not armed or armored; having no arms or weapons.
      [1913 Webster]

   2. (Nat. Hist.) Having no hard and sharp projections, as
      spines, prickles, spurs, claws, etc.
      [1913 Webster]

   3. Not in a state in which it may be detonated; unable to be
      detonated; -- used of nuclear and certain other explosive
      devices, which, as a safety precaution, are stored and
      transported in a state in which normal triggering
      mechanisms will not function to cause the device to
      detonate. The weapon must first be armed by a separate
      action, and only subsequent to such arming will the weapon
      be able to detonate.
      [PJC]

WordNet (r) 3.0 (2006):

unarmed
    adj 1: (used of persons or the military) not having or using
           arms; "went alone and unarmed"; "unarmed peasants were
           shot down"; "unarmed vehicles" [ant: armed]
    2: (used of plants or animals) lacking barbs or stings or thorns
       [ant: armed]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "unarmed":
   bare-handed, defenseless, disqualified, guardless, helpless,
   ill-equipped, ill-fitted, ill-furnished, ill-provided, incapable,
   incompetent, unadapted, unarmored, unattended, uncovered,
   undefended, unequipped, unfit, unfitted, unfortified, ungarrisoned,
   unguarded, unprotected, unprovided, unqualified, unscreened,
   unsheltered, unshielded, unsuited, unsuspecting, unwarned,
   unwatched, weaponless