anergy

from WordNet (r) 3.0 (2006)

anergy
    n 1: reduction or lack of an immune response to a specific
         antigen
    2: inactivity and lack of energy

from The Collaborative International Dictionary of English v.0.48

Anergia \An*er"gi*a\, Anergy \An"er*gy\, n. [NL. anergia, fr.
   Gr. ?- not + ? work.]
   Lack of energy; inactivity. -- {An*er"gic}, a.
   [Webster 1913 Suppl.]