baby daddy
noun [ C ] informal uk/ˈbeɪ.bi ˌdæd.i/ us/ˈbeɪ.bi ˌdæd.i/
孩子的爸爸（尤其在男女双方不再是情侣时）
the father of a woman's child, especially when he is not her husband and not in a relationship with her
Single moms out there, make your baby daddy take responsibility for their kids! 看那些单亲母亲，让孩子的爸爸为孩子负起责任来吧！