olive-drab uniform vs armed services

olive-drab uniform and armed services both are nouns.

Word	Noun	Adjective	Verb	Adverb
olive-drab uniform	Yes	No	No	No
armed services	Yes	No	No	No

olive-drab uniform (noun)	armed services (noun)
military uniform of the United States Army; made from cloth of a dull olive color	the military forces of a nation