Definition & Meaning of "[fall] on deaf ears"

What is the origin of the idiom "fall on deaf ears" and when to use it?

The idiom "fall on deaf ears" likely originated from the literal concept that if you speak or make a sound and the person you're addressing is deaf, your words won't be heard or understood. It has been in use since at least the 17th century and is a metaphorical expression that extends this idea to mean that your words or pleas are not being heeded or considered by someone who is not receptive. This expression is used to describe a situation where your words, requests, advice, or pleas are being ignored or disregarded by someone who is not interested in listening or responding. It implies a lack of receptiveness or empathy on the part of the listener.