Source : Webster's Revised Unabridged Dictionary (1913)

Accuser \Ac*cus"er\, n. [OE. acuser, accusour; cf. OF. acuseor,
   fr. L. accusator, fr. accusare.]
   One who accuses; one who brings a charge of crime or fault.

Source : WordNet®

accuser
     n : someone who imputes guilt or blame