ef ‧ fron ‧ te ‧ ry /ɪˈfrʌntəri/ BrE AmE noun [uncountable] formal
[ Date: 1600-1700 ; Language: French ; Origin: effronterie , from Late Latin effrons 'shameless' ]
rude behaviour that shocks you because it is so confident SYN nerve
have the effrontery to do something
She had the effrontery to ask me for more money.