pederast

from WordNet (r) 3.0 (2006)

pederast
    n 1: a man who has sex (usually sodomy) with a boy as the
         passive partner [syn: {pederast}, {paederast}, {child
         molester}]

from The Collaborative International Dictionary of English v.0.48

Pederast \Ped"er*ast\, n. [Gr. paiderasth`s; pai^s, paido`s, a
   boy + 'era^n to love: cf. F. p['e]d['e]raste.]
   One guilty of pederasty; a sodomite.
   [1913 Webster]