toughened vs hardened

toughened and hardened both are adjectives.

Word	Noun	Adjective	Verb	Adverb
toughened	No	Yes	No	No
hardened	No	Yes	No	No

As adjectives, toughened and hardened are synonyms defined as:

toughened and hardened: made hard or flexible or resilient especially by heat treatment

Other synonyms of toughened include tempered, treated.

toughened (adjective)	hardened (adjective)
physically toughened	made hard or flexible or resilient especially by heat treatment
made hard or flexible or resilient especially by heat treatment	protected against attack (especially by nuclear weapons)
	made tough by habitual exposure
	converted to solid form (as concrete)
	used of persons; emotionally hardened