Source : Webster's Revised Unabridged Dictionary (1913)

Dejected \De*ject"ed\, a.
   Cast down; afflicted; low-spirited; sad; as, a dejected look
   or countenance. -- {De*ject"ed*ly}, adv. --
   {De*ject"ed*ness}, n.

Deject \De*ject"\, v. t. [imp. & p. p. {Dejected}; p. pr. & vb.
   n. {Dejecting}.] [L. dejectus, p. p. of dejicere to throw
   down; de- + jacere to throw. See {Jet} a shooting forth.]
   1. To cast down. [Obs. or Archaic]

            Christ dejected himself even unto the hells.
                                                  --Udall.

            Sometimes she dejects her eyes in a seeming
            civility; and many mistake in her a cunning for a
            modest look.                          --Fuller.

   2. To cast down the spirits of; to dispirit; to discourage;
      to dishearten.

            Nor think, to die dejects my lofty mind. --Pope.

Source : WordNet®

dejected
     adj : affected or marked by low spirits; "is dejected but trying
           to look cheerful" [ant: {elated}]