to turn a deaf ear
Avisei ele várias vezes, mas ele fez ouvidos de mercador.
I warned him several times, but he turned a deaf ear.
The phrase pictures a mercador (merchant) who pretends not to hear. A trader haggling over goods would feign indifference to a customer's offer, acting as if deaf, to win better terms — so "having a merchant's ears" came to mean deliberately ignoring what one hears.
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