What is the idiom for to ignore a person and refuse speak him?

There isn't one single idiom that perfectly captures the act of completely ignoring someone and refusing to speak to them. However, several idioms come close, depending on the specific nuance you want to convey:

For complete avoidance and silence:

* Give the cold shoulder: This implies deliberate indifference and a refusal to engage.

* Cut someone dead: This is a more aggressive form of ignoring, suggesting complete rejection and disdain.

* Not speak to someone (for a period of time): This is a more direct and literal way to describe the situation.

For deliberate exclusion and withholding of attention:

* Turn a blind eye: This suggests intentional ignorance of someone's presence.

* Not acknowledge someone's presence: This emphasizes the complete lack of interaction.

For showing disapproval and anger:

* Give someone the silent treatment: This implies withholding communication as a form of punishment or disapproval.

* Send someone to Coventry: This is a less common idiom meaning to ostracize someone and avoid all contact.

The best idiom to use will depend on the specific context and the emotional tone you want to convey.