Source : Webster's Revised Unabridged Dictionary (1913)

Energizer \En"er*gi`zer\, n.
   One who, or that which, gives energy, or acts in producing an
   effect.

Source : WordNet®

energizer
     n 1: someone who imparts energy and vitality and spirit to other
          people [syn: {energiser}, {vitalizer}, {vitaliser}, {animator}]
     2: a device that supplies electrical energy [syn: {energiser}]