The Collaborative International Dictionary of English v.0.48:
Listener \Lis"ten*er\ (l[i^]s"'n*[~e]r), n. One who listens; a hearkener. [1913 Webster]WordNet (r) 3.0 (2006):
listener n 1: someone who listens attentively [syn: hearer, listener, auditor, attender]