accuser

from WordNet (r) 3.0 (2006)

accuser
    n 1: someone who imputes guilt or blame

from The Collaborative International Dictionary of English v.0.48

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.
   [1913 Webster]

from Easton's 1897 Bible Dictionary

Accuser
Satan is styled the "accuser of the brethren" (Rev. 12:10. Comp.
Job 1:6; Zech. 3:1), as seeking to uphold his influence among
men by bringing false charges against Christians, with the view
of weakening their influence and injuring the cause with which
they are identified. He was regarded by the Jews as the accuser
of men before God, laying to their charge the violations of the
law of which they were guilty, and demanding their punishment.
The same Greek word, rendered "accuser," is found in John 8:10
(but omitted in the Revised Version); Acts 23:30, 35; 24:8;
25:16, 18, in all of which places it is used of one who brings a
charge against another.