noun
[ pl. ] ordinary clothes, not uniform, when worn by police officers on duty :
officers in plain clothes
► ˌplain-ˈclothes adjective [ only before noun ]:
plain-clothes police officers
noun
[ pl. ] ordinary clothes, not uniform, when worn by police officers on duty :
officers in plain clothes
► ˌplain-ˈclothes adjective [ only before noun ]:
plain-clothes police officers
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005