Source : Webster's Revised Unabridged Dictionary (1913)

Caitiff \Cai"tiff\, a. [OE. caitif, cheitif, captive, miserable,
   OF. caitif, chaitif, captive, mean, wretched, F. ch['e]tif,
   fr. L. captivus captive, fr. capere to take, akin to E.
   heave. See {Heave}, and cf. {Captive}.]
   1. Captive; wretched; unfortunate. [Obs.] --Chaucer.

   2. Base; wicked and mean; cowardly; despicable.

            Arnold had sped his caitiff flight.   --W. Irving.

Caitiff \Cai"tiff\, n.
   A captive; a prisoner. [Obs.]

         Avarice doth tyrannize over her caitiff and slave.
                                                  --Holland.

   2. A wretched or unfortunate man. [Obs.] --Chaucer.

   3. A mean, despicable person; one whose character meanness
      and wickedness meet.

   Note: The deep-felt conviction of men that slavery breaks
         down the moral character . . . speaks out with . . .
         distinctness in the change of meaning which caitiff has
         undergone signifying as it now does, one of a base,
         abject disposition, while there was a time when it had
         nothing of this in it. --Trench.

Source : WordNet®

caitiff
     adj : despicably mean and cowardly
     n : a cowardly and despicable person