The Collaborative International Dictionary of English v.0.48:

Hearer \Hear"er\ (h[=e]r"[~e]r), n.
   One who hears; an auditor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hearer
    n 1: someone who listens attentively [syn: hearer, listener,
         auditor, attender]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "hearer":
   accepter, acquirer, addressee, audience, audient, auditor,
   beholder, consignee, eavesdropper, getter, hearkener, holder,
   listener, looker, obtainer, overhearer, payee, procurer, receiver,
   recipient, snoop, spectator, taker, trustee, viewer