comme il faut
adjective [ after verb ] formal uk/ˌkɒm ɪl ˈfəʊ/ us/ˌkɑːm ɪl ˈfoʊ/
适当的，合乎礼仪的
behaving or dressing in the right way in public according to formal rules of social behaviour
Trust me - it's not comme il faut to wear a pink tie to a funeral. 相信我——系粉色领带参加葬礼不合适。
Synonym: seemly