civvies vs civilian dress

civvies and civilian dress both are nouns.

Word	Noun	Adjective	Verb	Adverb
civvies	Yes	No	No	No
civilian dress	Yes	No	No	No

As nouns, civilian dress is a hypernym of civvies; that is, civilian dress is a word with a broader meaning than civvies:

civvies: civilian garb as opposed to a military uniform
civilian dress: ordinary clothing as distinguished from uniforms, work clothes, clerical garb, etc.

Other hypernyms of civvies include civilian clothing, civilian garb, plain clothes.

civvies (noun)	civilian dress (noun)
civilian garb as opposed to a military uniform	ordinary clothing as distinguished from uniforms, work clothes, clerical garb, etc.