Source : Webster's Revised Unabridged Dictionary (1913)

Mammon \Mam"mon\, n. [L. mammona, Gr. ? riches, Syr. mam?n[=a];
   cf. Heb. matm?n a hiding place, subterranean storehouse,
   treasury, fr. t[=a]man to hide.]
   Riches; wealth; the god of riches; riches, personified.

         Ye can not serve God and Mammon.         --Matt. vi.
                                                  24.

Source : WordNet®

mammon
     n 1: wealth regarded as an evil influence
     2: (New Testament) a personification of wealth and avarice as
        an evil spirit; "ye cannot serve God and Mammon"