diplomatic relations
noun [ plural ] uk/ˌdɪp.lə.mæt.ɪk rɪˈleɪ.ʃənz/ us/ˌdɪp.lə.mæt̬.ɪk rɪˈleɪ.ʃənz/
外交关系
the arrangement between two countries by which each has representatives in the other country
Britain threatened to break off diplomatic relations. 英国威胁说要断绝外交关系。