brass neck
1. noun Self-assured shamelessness, audacity, confidence, gall, or impudence. Primarily heard in UK. It takes a brass neck to make such an outlandish demand of me. The junior minister has shown a brass neck to the public regarding his plans to cut social welfare.
2. noun A person displaying or characterized by self-assured shamelessness, audacity, confidence, gall, or impudence. Primarily heard in UK. It's beyond me how a brass neck like him could be appointed as a manager.
3. verb To act with courageous self-confidence, especially in an audacious, impudent, or shameless manner. Primarily heard in UK. We didn't have enough money for the train ride, but we thought we'd just brass neck it if anyone gave us grief.