Source : Webster's Revised Unabridged Dictionary (1913)

Forearm \Fore*arm"\, v. t.
   To arm or prepare for attack or resistance before the time of
   need. --South.

Forearm \Fore"arm`\, n. (Anat.)
   That part of the arm or fore limb between the elbow and
   wrist; the antibrachium.

Source : WordNet®

forearm
     n : the part of the superior limb between the elbow and the
         wrist
     v : arm in advance of a confrontation