1.
in one ear and out the other; paying no attention
Completely ignoring what is said, like an east wind blowing past a horse's ears.
Etymology
馬耳 (horse's ears) + 東風 (east wind)
From a Chinese poem by 李白 (Li Bai). The east wind is the spring breeze, which carries the scent of flowers—but a horse pays no attention to it.
Usage
Describes someone who completely ignores advice, warnings, or opinions. The implication is often critical—the person should be listening but isn't.
Often used to describe people who don't take criticism or advice seriously.