Source : Webster's Revised Unabridged Dictionary (1913)

Demerit \De*mer"it\, n. [F. d['e]m['e]rite demerit (in sense 2),
   OF. demerite demerit (in sense 1), fr. L. demerere to deserve
   well, LL., to deserve well or ill; de- + merere to deserve.
   See {De}-, and {Merit}.]
   1. That which one merits or deserves, either of good or ill;
      desert. [Obs.]

            By many benefits and demerits whereby they obliged
            their adherents, [they] acquired this reputation.
                                                  --Holland.

   2. That which deserves blame; ill desert; a fault; a vice;
      misconduct; -- the opposite of {merit}.

            They see no merit or demerit in any man or any
            action.                               --Burke.

            Secure, unless forfeited by any demerit or offense.
                                                  --Sir W.
                                                  Temple.

   3. The state of one who deserves ill.

Demerit \De*mer"it\, v. t. [Cf. F. d['e]m['e]riter to deserve
   ill. See {Demerit}, n.]
   1. To deserve; -- said in reference to both praise and blame.
      [Obs.]

            If I have demerited any love or thanks. --Udall.

            Executed as a traitor . . . as he well demerited.
                                                  --State Trials
                                                  (1645).

   2. To depreciate or cry down. [R.] --Bp. Woolton.

Demerit \De*mer"it\, v. i.
   To deserve praise or blame.

Source : WordNet®

demerit
     n 1: a mark against a person for misconduct or failure; usually
          given in school or armed forces; "ten demerits and he
          loses his privileges"
     2: the quality of being inadequate or falling short of
        perfection; "they discussed the merits and demerits of her
        novel"; "he knew his own faults much better than she did"
        [syn: {fault}] [ant: {merit}]