civvies vs civilian garb

civvies and civilian garb both are nouns.

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

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

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

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

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