The Collaborative International Dictionary of English v.0.48:

malcontent \mal"con*tent`\, a. [F., fr. mal ill + content. See
   Malice, Content.]
   discontented; uneasy; dissatisfied; especially, dissatisfied
   with the government. [Written also malecontent.]
   [1913 Webster]

         The famous malcontent earl of Leicester. --Milner.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Malcontent \Mal"con*tent`\, n. [F. malcontent.]
   One who discontented; especially, a discontented subject of a
   government; one who expresses his discontent by words or
   overt acts. --Spenser. --Berkeley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

malcontent
    adj 1: discontented as toward authority [syn: disaffected,
           ill-affected, malcontent, rebellious]
    n 1: a person who is discontented or disgusted

Moby Thesaurus II by Grady Ward, 1.0:

101 Moby Thesaurus words for "malcontent":
   agitator, alienated, anarch, anarchist, beefing, bellyacher,
   bellyaching, bitching, brawler, complainant, complainer,
   complaining, complaintful, contumacious, crab, crabbing, crabby,
   crank, cranky, croaker, croaking, disaffected, disappointed,
   discontent, discontented, disgruntled, disobedient, displeased,
   dissatisfied, envious, estranged, extremist, factious, faultfinder,
   faultfinding, frondeur, griever, griper, griping, grouch, grouchy,
   grouser, grousing, growler, growling, grumbler, grumbling,
   insubordinate, insurgent, insurrectionary, insurrectionist,
   insurrecto, kicker, killjoy, kvetch, lamenter, malcontented,
   maverick, mourner, murmurer, murmuring, mutineer, mutterer,
   muttering, nonconformist, out of humor, peevish, petulant,
   querulant, querulous, querulous person, reactionary, reactionist,
   rebel, rebellious, resentful, restive, restless, revolter,
   revolutionary, revolutionist, rioter, seditious, sorehead,
   sourpuss, spoilsport, subversive, sulky, traitor, unaccepting,
   unaccommodating, uneasy, unfulfilled, ungovernable, ungratified,
   unhappy, unruly, unsatisfied, wet blanket, whiner, whiny