Source : Webster's Revised Unabridged Dictionary (1913)

Mercenary \Mer"ce*na*ry\, a. [OE. mercenarie, F. mercenaire, fr.
   L. mercenarius, fr. merces wages, reward. See {Mercy}.]
   1. Acting for reward; serving for pay; paid; hired; hireling;
      venal; as, mercenary soldiers.

   2. Hence: Moved by considerations of pay or profit; greedy of
      gain; sordid; selfish. --Shak.

            For God forbid I should my papers blot With
            mercenary lines, with servile pen.    --Daniel.

   Syn: See {Venal}.

Mercenary \Mer"ce*na*ry\, n.; pl. {Mercenaries}.
   One who is hired; a hireling; especially, a soldier hired
   into foreign service. --Milman.

Source : WordNet®

mercenary
     adj 1: marked by materialism [syn: {materialistic}, {worldly-minded}]
     2: used of soldiers hired by a foreign army [syn: {mercenary(a)},
         {freelance(a)}]
     3: profit oriented; "a commercial book"; "preached a mercantile
        and militant patriotism"- John Buchan; "a mercenary
        enterprise"; "a moneymaking business" [syn: {mercantile},
        {moneymaking(a)}]
     n : a person hired to fight for another country than their own
         [syn: {soldier of fortune}]