Source : Webster's Revised Unabridged Dictionary (1913)

Inefficient \In`ef*fi"cient\, a.
   1. Not efficient; not producing the effect intended or
      desired; inefficacious; as, inefficient means or measures.

   2. Incapable of, or indisposed to, effective action;
      habitually slack or remiss; effecting little or nothing;
      as, inefficient workmen; an inefficient administrator.

Source : WordNet®

inefficient
     adj 1: not producing desired results; wasteful; "an inefficient
            campaign against drugs"; "outdated and inefficient
            design and methods" [ant: {efficient}]
     2: lacking the ability or skill to perform effectively;
        inadequate; "an ineffective administration"; "inefficient
        workers" [syn: {ineffective}]