behaviour that is confident and very rude, without any feeling of shame 厚颜无耻的行为；傲慢鲁莽的举止 He had the effrontery to accuse me of lying! 他无礼地指责我撒谎！
Word Originlate 17th cent.: from French effronterie, based on late Latin effrons, effront- ‘shameless, barefaced’, from ex- ‘out’ + frons ‘forehead’.