legionnaire vs legionary

legionnaire and legionary both are nouns.

Word	Noun	Adjective	Verb	Adverb
legionnaire	Yes	No	No	No
legionary	Yes	No	No	No

As nouns, legionnaire and legionary are synonyms defined as:

legionnaire and legionary: a soldier who is a member of a legion (especially the French Foreign Legion)

legionnaire (noun)	legionary (noun)
a soldier who is a member of a legion (especially the French Foreign Legion)	a soldier who is a member of a legion (especially the French Foreign Legion)