The Collaborative International Dictionary of English v.0.48:

nonverbal \nonverbal\, non-verbal \non-verbal\adj.
   Involving little or no use of language; as, gestures are a
   form of nonverbal communication.

   Syn: non-verbal.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

nonverbal
    adj 1: being other than verbal communication; "the study of
           gestural communication"; "art like gesture is a form of
           nonverbal expression" [syn: gestural, nonverbal]
    2: lacking verbal skill; "rural students often come from
       nonverbal backgrounds"
    3: involving little use of language; "a nonverbal intelligence
       test"