harden vs temper

harden is not a noun while temper is a noun.

Word	Noun	Adjective	Verb	Adverb
harden	No	No	Yes	No
temper	Yes	No	Yes	No

As verbs, temper is a hyponym of harden; that is, temper is a word with a more specific, narrower meaning than harden:

harden: make hard or harder
temper: bring to a desired consistency, texture, or hardness by a process of gradually heating and cooling

Other hyponyms of harden include face-harden, callus, anneal, normalize.

As verbs, harden and temper are synonyms defined as:

harden (noun)	temper (noun)
	the elasticity and hardness of a metal object; its ability to absorb considerable energy before cracking
	a disposition to exhibit uncontrolled anger
	a characteristic (habitual or relatively temporary) state of feeling
	a sudden outburst of anger

harden (verb)	temper (verb)
become hard or harder	make more temperate, acceptable, or suitable by adding something else
make hard or harder	adjust the pitch (of pianos)
make healthy	harden by reheating and cooling in oil
cause to accept or become hardened to; habituate	change by restraining or moderating
harden by reheating and cooling in oil	bring to a desired consistency, texture, or hardness by a process of gradually heating and cooling