military adviser vs advisor

military adviser and advisor both are nouns.

Word	Noun	Adjective	Verb	Adverb
military adviser	Yes	No	No	No
advisor	Yes	No	No	No

As nouns, advisor is a hypernym of military adviser; that is, advisor is a word with a broader meaning than military adviser:

military adviser: a military officer who serves as an adviser to the troops of an allied nation
advisor: an expert who gives advice

Other hypernyms of military adviser include adviser, consultant, military officer, officer.

military adviser (noun)	advisor (noun)
a military officer who serves as an adviser to the troops of an allied nation	an expert who gives advice