shameless: implies a lack of effective restraints, such as modesty, an active conscience, or a sense of decency: told a ~ lie.


brazen: adds to shameless an implication of defiant insolence: stood up to him with ~ arrogance.


barefaced: implies absence of all efforts to disguise or mask one's transgressions and connotes extreme effrontery: a ~lie.  （effrontery无耻无礼implies disregard of courtesy or propriety拒绝考虑礼貌礼节,可见和本组最后一个词相同, 如had the effrontery to tell me how to do my job无耻地告诉我怎么工作(表现为无礼)）


brash: stresses impetuousness and may imply heedlessness and temerity: won them over with his ~ but charming manner.  （impetuous冲动莽撞: 表示非常冲动没耐心stresses extreme impatience or impulsiveness,如it is a bit impetuous to propose marriage on the third date第三次约会就求婚有点冲动，这个词很好记因为三个词都以imp开头。冲动不一定贬义，在《君主论》倒数第2章，马基雅维利说: "I certainly think that it is better to be impetuous than cautious, for fortune is a woman ...我确信冲动好于慎重，因为命运是个女人...她喜欢1是胆大2是年轻的人"）  （temerity大胆无礼（贬）: rashness and contempt of danger不考虑后果，比如被拒绝嘲讽，如had the temerity to ask for a favor after that insult那次侮辱后又胆大无礼地求人帮忙）  （audacity表示不考虑常规谨慎限制显得大胆，一般是褒义implies a disregard of restraints commonly imposed by convention or prudence, 如an entrepreneur with audacity and vision一个兼具胆量和眼光的企业家，the audacity of hope是奥巴马写的书《大胆希望》）


impudent: adds to shameless implications of bold or pert defiance of consideration of modesty or decency: a rude and ~ reply to a polite question.


shameless无耻: 指缺乏应有的克制，如谦虚体面良知，brazen无耻且傲慢: 在无耻基础上增加了傲慢不服从的意思（defy拒不服从），barefaced恬不知耻: 指毫不掩饰过错，显得十分无礼，brash冲动自信: 强调做事冲动莽撞不顾忌，impudent无礼: 拒不考虑谦虚体面

记忆方法：1）首字母IS BBB是3个B<==无耻

          2） 无耻的意思是大胆无羞耻mean characterized by boldness and a lack of sense of shame.