hardy vs stalwart

hardy is not a noun while stalwart is a noun.

Word	Noun	Adjective	Verb	Adverb
hardy	No	Yes	No	No
stalwart	Yes	Yes	No	No

As adjectives, hardy and stalwart are synonyms defined as:

hardy and stalwart: having rugged physical strength; inured to fatigue or hardships

Other synonyms of hardy include stout, sturdy.

hardy (noun)	stalwart (noun)
	a person who is loyal to their allegiance (especially in times of revolt)

hardy (adjective)	stalwart (adjective)
invulnerable to fear or intimidation	used especially of persons
having rugged physical strength; inured to fatigue or hardships	dependable
able to survive under unfavorable weather conditions	having rugged physical strength; inured to fatigue or hardships