tempered vs toughened

tempered and toughened both are adjectives.

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

As adjectives, tempered and toughened are synonyms defined as:

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

Other synonyms of tempered include hardened, treated.

tempered (adjective)	toughened (adjective)
adjusted or attuned by adding a counterbalancing element	physically toughened
made hard or flexible or resilient especially by heat treatment	made hard or flexible or resilient especially by heat treatment