co-respondent
noun [ C ] law specialized uk/ˌkəʊ.rɪˈspɒn.dənt/ us/ˌkoʊ.rəˈspɑːn.dənt/
（与他人配偶通奸的）共同被告
the person who a married person is said to have committed adultery (= sex outside marriage) with
He was cited/named as co-respondent in the divorce. 他作为该离婚案的共同被告被传讯。
Compare: respondent