Have the brass (neck) to (do something) British phrase informal
If someone "has the brass neck to do something", he/she has the confidence or the will to do something that is considered unacceptable or daring to others.
She had the brass neck to arrive an hour late at the meeting, didn't she?
I have to admit that I don't have the brass neck to play truant in Mr.Simpson's class.
If she had got the brass neck to bargain with the salesman, she wouldn't have paid for a lower price.
The verb "have" should be conjugated according to their tense.
The phrase dates from the 1960s.