de·fi·cient 
(dĭ-fĭshənt)
(dĭ-fĭshənt)adj.
1. Lacking an essential quality or element: deficient in common sense.
2. Inadequate in amount or degree; insufficient: a deficient education.
[Latin dēficiēns, dēficient-, present participle of dēficere, to fail, be wanting; see DEFECT.]
de·ficient n.
de·ficient·ly adv.