noun
straining one's ears; listening intently
Refers to the act of listening carefully, often to catch faint or distant sounds. Commonly used in the phrase 聞き耳を立てる (to prick up one's ears).
隣の部屋の話を聞き耳を立てて聞いていた。
I was straining my ears to listen to the conversation in the next room.
彼はドアの外で聞き耳を立てた。
He pricked up his ears outside the door.
Rare variant without okurigana.
Implies eavesdropping with a negative or secretive nuance, while 聞き耳 is more neutral and simply means listening intently.
Compound of 聞き (kiki, 'listening', the continuative form of 聞く) and 耳 (mimi, 'ear').