Civies are the civilian clothing worn instead of military or uniform clothing. Civvy, mufti, and plainclothes are some synonyms for civies. These terms are commonly used in military and law enforcement sectors to refer to the ordinary clothes worn when off duty. Civvy or civvie is a British term, and mufti is an old military slang word, usually used by the Navy. Plainclothes, as the name suggests, is the dress code for law enforcement agents. These words are interchangeable and can be used in different contexts, but they connote the same meaning as civies.