deficiency in WordNet English dictionary

1. lack of an adequate quantity or number
   "the inadequacy of unemployment benefits"
   insufficiency  inadequacy  deficiency 
   
2. the state of needing something that is absent or unavailable
   "there is a serious lack of insight into the problem"; "water is the critical deficiency in desert regions"; "for want of a nail the shoe was lost"
   lack  deficiency  want