The Collaborative International Dictionary of English v.0.48:

Gesticulate \Ges*tic"u*late\, v. i. [imp. & p. p.
   Gesticulated; p. pr. & vb. n. Gesticulating.] [L.
   gesticulatus, p. p. of gesticulari to gesticulate, fr.
   gesticulus a mimic gesture, gesticulation, dim. of gestus
   gesture, fr. gerere, gestum, to bear, carry, peform. See
   Gestic.]
   To make gestures or motions, as in speaking; to use postures.
   --Sir T. Herbert.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gesticulating
    adj 1: making gestures while speaking; "her gesticulating hands
           and arms made words almost unnecessary"