The Collaborative International Dictionary of English v.0.48:

endoergic \endoergic\ adj.
   occurring with absorption of energy. [Narrower terms:
   endothermic] exoergic

   Syn: energy-absorbing.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

endoergic
    adj 1: (of a nuclear reaction) occurring with absorption of
           energy [syn: endoergic, energy-absorbing] [ant:
           energy-releasing, exoergic]