Synonyms and related words :
attend, attend to, auscultate, be all ears, bend an ear, bug, cock the ears, examine by ear, give attention, give audience to, give ear, hark, hear, hear out, hearken, heed, intercept, lend an ear, listen, listen at, listen in, listen to, overhear, pry, sit in on, snoop, spy, tap, wiretap