attend attend to auscultate be all ears bend an ear bug bugging cloak-and-dagger work cock the ears counterespionage counterintelligence eavesdrop electronic surveillance espial espionage examine by ear following give attention give audience to give ear hark hear hear out hearken heed intelligence intelligence work intercept lend an ear listen listen at listen in listen to military intelligence observation secret police secret service shadowing sit in on spying stakeout surveillance tailing tap trailing wiretapping