ineptness

from WordNet (r) 3.0 (2006)

ineptness
    n 1: unskillfulness resulting from a lack of training [syn:
         {awkwardness}, {clumsiness}, {ineptness}, {ineptitude},
         {maladroitness}, {slowness}]
    2: the quality of having the wrong properties for a specific
       purpose [syn: {unsuitability}, {unsuitableness}, {ineptness}]
       [ant: {suitability}, {suitableness}]

from The Collaborative International Dictionary of English v.0.48

Ineptness \In*ept"ness\, n.
   Unfitness; ineptitude.
   [1913 Webster]

         The feebleness and miserable ineptness of infancy.
                                                  --Dr. H. More.
   [1913 Webster]