listen in onsth/sb
—phrasal verbwithlistenverb[I]uk/ˈlɪs.ən/us/ˈlɪs.ən/
C2
If youlistenin on aconversationor on someonetalking, youlisten,especiallysecretly, without saying anything.
偷听，窃听
IwishDad wouldstoplisteningin on myphoneconversations.我希望爸爸不再偷听我的电话。