The Collaborative International Dictionary of English v.0.48:

Discontent \Dis`con*tent"\, v. t. [imp. & p. p. Discontented;
   p. pr. & vb. n. Discontenting.]
   To deprive of content; to make uneasy; to dissatisfy.
   --Suckling.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Discontented \Dis`con*tent"ed\, p. p. & a.
   Dissatisfied; uneasy in mind; malcontent.
   [1913 Webster]

         And every one that was in distress, and every one that
         was in debt, and every one that was discontented,
         gathered themselves unto him.            --1 Sam. xxii.
                                                  2.
   -- Dis`con*tent"ed*ly, adv. -- Dis`con*tent"ed*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

discontented
    adj 1: showing or experiencing dissatisfaction or restless
           longing; "saw many discontent faces in the room"; "was
           discontented with his position" [syn: discontented,
           discontent] [ant: content, contented]

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "discontented":
   acid, against, angry, annoyed, beefing, bellyaching, bitching,
   browned off, caustic, cheerless, complaining, complaintful, con,
   corrosive, crabbing, crabby, cranky, croaking, disappointed,
   disapprobatory, disapproving, discontent, disenchanted,
   disgruntled, disillusioned, displeased, dissatisfied, dissenting,
   envious, exasperated, faultfinding, fed up, feeling evil, fretful,
   grim, griping, grouchy, grousing, growling, grumbling, humorless,
   in bad humor, indignant, infestive, irritated, joyless, low,
   malcontent, malcontented, mirthless, miserable, murmuring,
   muttering, opposed, opposing, out of humor, out of sorts,
   out of temper, peevish, petulant, piqued, pissed off, pleasureless,
   poor, querulant, querulous, rebellious, resentful, restive,
   restless, sorry, sorryish, sulky, testy, turned-off, unaccepting,
   unaccommodating, unappreciative, unapproving, uncheerful, uncheery,
   uncomplimentary, uneasy, unfavorable, unfulfilled, ungratified,
   unhappy, unjoyful, unmirthful, unsatisfied, unsmiling, vexed,
   whiny, wretched