unfitness

from WordNet (r) 3.0 (2006)

unfitness
    n 1: poor physical condition; being out of shape or out of
         condition (as from a life of ease and luxury) [syn:
         {unfitness}, {softness}] [ant: {fitness}, {physical
         fitness}]
    2: lacking the power to perform [syn: {inability}, {unfitness}]
       [ant: {ability}]
    3: the quality of not being suitable; "the judges agreed on his
       unfitness for the appointment" [ant: {fitness},
       {fittingness}]

from The Collaborative International Dictionary of English v.0.48

Unfit \Un*fit"\, a. [Pref. un- + fit.]
   Not fit; unsuitable. -- {Un*fit"ly}, adv. -- {Un*fit"ness},
   n.
   [1913 Webster]