- (当事双方以外的人或团体; [谑]三角关系中的第三者) a third party (to a dispute, etc.); tertium quid; “the third person”; mistress; lover; the outside man or woman; the other man or the other woman:
Their marriage has broken just because of the other man.
他们婚姻的破裂仅仅因为有第三者插足。