defrost vs thaw

defrost is not a noun while thaw is a noun.

Word	Noun	Adjective	Verb	Adverb
defrost	No	No	Yes	No
thaw	Yes	No	Yes	No

As verbs, thaw is a hypernym of defrost; that is, thaw is a word with a broader meaning than defrost:

Other hypernyms of defrost include dethaw, dissolve, melt, unfreeze, unthaw.

defrost (noun)	thaw (noun)
	a relaxation or slackening of tensions or reserve; becoming less hostile
	warm weather following a freeze; snow and ice melt
	the process whereby heat changes something from a solid to a liquid

defrost (verb)	thaw (verb)
make or become free of frost or ice	become or cause to become soft or liquid