vanguard vs army unit

vanguard and army unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
vanguard	Yes	No	No	No
army unit	Yes	No	No	No

As nouns, army unit is a hypernym of vanguard; that is, army unit is a word with a broader meaning than vanguard:

vanguard (noun)	army unit (noun)
the position of greatest importance or advancement; the leading position in any movement or field	a military unit that is part of an army
the leading units moving at the head of an army
any creative group active in the innovation and application of new concepts and techniques in a given field (especially in the arts)