staying power vs toughness

staying power and toughness both are nouns.

Word	Noun	Adjective	Verb	Adverb
staying power	Yes	No	No	No
toughness	Yes	No	No	No

As nouns, staying power and toughness are synonyms defined as:

Other synonyms of staying power include stamina.

staying power (noun)	toughness (noun)
enduring strength and energy	the property of being big and strong
	enduring strength and energy
	impressive difficulty
	the elasticity and hardness of a metal object; its ability to absorb considerable energy before cracking