The Collaborative International Dictionary of English v.0.48:

Disarm \Dis*arm"\, v. t. [imp. & p. p. Disarming; p. pr. & vb.
   n. Disarming.] [OE. desarmen, F. d['e]sarmer; pref. d['e]s-
   (L. dis-) + armer to arm. See Arm.]
   1. To deprive of arms; to take away the weapons of; to
      deprive of the means of attack or defense; to render
      defenseless.
      [1913 Webster]

            Security disarms the best-appointed army. --Fuller.
      [1913 Webster]

            The proud was half disarmed of pride. --Tennyson.
      [1913 Webster]

   2. To deprive of the means or the disposition to harm; to
      render harmless or innocuous; as, to disarm a man's wrath.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

disarming \disarming\ adj.
   1. capable of allaying suspicion or hostility and inspiring
      confidence; as, a disarming smile.
      [WordNet 1.5]

   2. capable of allaying hostility.
      [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

disarming \disarming\ n.
   act of reducing or depriving of weapons.

   Syn: disarmament.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

disarming
    adj 1: capable of allaying hostility
    n 1: act of reducing or depriving of arms; "the disarmament of
         the aggressor nations must be complete" [syn: disarming,
         disarmament] [ant: armament, arming, equipping]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "disarming":
   bland, buttery, deferential, fair-spoken, fine-spoken, fulsome,
   glib, honey-mouthed, honey-tongued, ingratiating, insinuating,
   insinuative, oily, oily-tongued, saccharine, silken, silky, smooth,
   smooth-spoken, smooth-tongued, smug, soapy, soft-spoken, suave,
   suave-spoken, unctuous