What is the meaning of idiomatic expression hard hearing?

The expression "hard of hearing" is not an idiom. It is a literal description of someone who has difficulty hearing. It is a more polite way of saying "deaf" or "hearing impaired."

However, there are idiomatic expressions that relate to not listening or ignoring someone, such as:

* Turning a deaf ear: This means to ignore someone or refuse to listen to what they are saying.

* Falling on deaf ears: This means that someone is not paying attention or is ignoring what you are saying.

* Be deaf to: This means to be unable or unwilling to hear or understand something.

It's important to distinguish between the literal meaning of "hard of hearing" and these idioms, which have figurative meanings.