civilian garb vs civies

civilian garb and civies both are nouns.

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

As nouns, civies is a hyponym of civilian garb; that is, civies is a word with a more specific, narrower meaning than civilian garb:

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

Other hyponyms of civilian garb include civvies, mufti.

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