hardening vs solidifying

hardening and solidifying both are nouns.

Word	Noun	Adjective	Verb	Adverb
hardening	Yes	No	No	No
solidifying	Yes	No	No	No

As nouns, hardening and solidifying are synonyms defined as:

hardening and solidifying: the process of becoming hard or solid by cooling or drying or crystallization

Other synonyms of hardening include curing, set, solidification.

hardening (noun)	solidifying (noun)
the act of making something harder (firmer or tighter or more compact)	the process of becoming hard or solid by cooling or drying or crystallization
the process of becoming hard or solid by cooling or drying or crystallization
abnormal hardening or thickening of tissue