disclaim: implies a refusal to accept either a rightful claim or an imputation made by another: ~ed in equal measure the virtues and vices attributed to her.  （rightful有2个意思 1、合法的according to the law，如the property's rightful owner财产的合法主人 2、合理合适的proper or appropriate，如the leader's rightful place in history books领导人在历史书中应有的地位）


disavow: implies a vigorous denial of personal responsibility, acceptance, or approval: the radical group ~ed any responsibility for the bombing.


repudiate: implies a rejection or denial of something that had been previously acknowledged, recognized, or accepted: ~d the socialist views of his college days.


disown: implies a vigorous rejection or renunciation of something with which one formerly had a close relationship: ~ed his allegiance to the country of his birth.   (renounce断绝弃绝often equals abjure but may carry the meaning of disclaim or disown比abjure多了否认断绝的意思，如willing to renounce his lifelong friends愿意和交往一辈子的朋友绝交。可见disown和renounce互释）


disallow: implies the withholding of sanction or approval and sometimes suggests complete rejection or condemnation: IRS auditors ~ed that deduction.  （sanction批准，表示官方正式的赞成official approval，如these changes will require the sanction of the court这些变更须经法院批准，如he may now be ready to sanction the use of force他现在可能打算批准使用武力）


disclaim否认: 指拒绝接受或正当声索或指责，disavow否认: 指坚决否认自己有责任，或曾接受赞成，repudiate否认丢弃: 指之前承认接受过，disown断绝: 表示被拒绝放弃的之前和自己有紧密关系，disallow不允许: 指拒绝给予批准赞成，或表示禁止甚至谴责

记忆方法: 1）首字母DDRDD想成四大皆除rid<==否认

         2）否认的意思是拒绝承认接受赞成mean to refuse to admit, accept, or approve.