Source : Webster's Revised Unabridged Dictionary (1913)

Mountaineer \Moun`tain*eer"\, n. [OF. montanier, LL.
   montanarius. See {Mountain}.]
   1. An inhabitant of a mountain; one who lives among
      mountains.

   2. A rude, fierce person. [Obs.]

            No savage fierce, bandit, or mountaineer. --Milton.

Mountaineer \Moun`tain*eer"\, v. i.
   To lie or act as a mountaineer; to climb mountains.

         You can't go mountaineering in a flat country. --H.
                                                  James.

Source : WordNet®

mountaineer
     n : someone who climbs mountains [syn: {mountain climber}]
     v : climb mountains for pleasure as a sport