The Collaborative International Dictionary of English v.0.48:

Boar \Boar\ (b[=o]r), n. [OE. bar, bor, bore, AS. b[=a]r; akin
   to OHG. p[=e]r, MHG. b[=e]r, G. b[aum]r, boar (but not
   b[aum]r bear), and perh. Russ. borov' boar.] (Zool.)
   The uncastrated male of swine; specifically, the wild hog.
   [1913 Webster]

WordNet (r) 3.0 (2006):

boar
    n 1: Old World wild swine having a narrow body and prominent
         tusks from which most domestic swine come; introduced in
         United States [syn: wild boar, boar, Sus scrofa]
    2: an uncastrated male hog