onerous

onerous
    adj 1: not easily borne; wearing; "the burdensome task of
           preparing the income tax return"; "my duties weren't
           onerous; I only had to greet the guests"; "a taxing
           schedule" [syn: {burdensome}, {onerous}, {taxing}]
    

Onerous \On"er*ous\, a. [L. onerosus, fr. onus, oneris, a load,
   burden: cf. F. on['e]reux.]
   Burdensome; oppressive. "Too onerous a solicitude." --I.
   Taylor.
   [1913 Webster]

   {Onerous cause} (Scots Law), a good and legal consideration;
      -- opposed to {gratuitous}.
      [1913 Webster]
    

70 Moby Thesaurus words for "onerous":
      Herculean, annoying, arduous, arduously, backbreaking, besetting,
      bothersome, burdensome, burdensomely, crushing, cumbersome,
      cumbrous, demanding, difficult, difficultly, effortful,
      encumbering, exacting, exhausting, exigent, forced, grievous,
      grinding, grueling, hampering, hard, hard-earned, hard-fought,
      hardly, harsh, heavy, heavy-handed, hefty, impedimental, impeding,
      impeditive, incumbent, irksome, killing, labored, laborious,
      laboriously, lumpish, massive, onerously, operose, oppressive,
      overburdensome, painful, plaguey, ponderous, punishing, strained,
      strenuous, superincumbent, taxing, toilsome, toilsomely, tough,
      troublesome, trying, tyrannous, unruly, unwieldy, uphill,
      vexatious, wearing, wearisome, wearying, weighty