un•der•charge
  Pronunciation: (v.un"dur-chärj'n.un'dur-chärj"), [key]    — v., n. -charged, -charg•ing, 
  
  
 —v.t.  - to charge (a purchaser) less than the proper or fair price.  
  - to charge (a stated amount) less than the proper price: They undercharged several dollars for storing the goods. 
  - to put an insufficient charge or load into.  
  
  
 —v.i.  - to charge too little.  
  
  
 —n.  - a charge or price less than is proper or customary.  
  - an insufficient charge or load.  
  
  
  Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.