insure vs guarantee

insure is not a noun while guarantee is a noun.

Word	Noun	Adjective	Verb	Adverb
insure	No	No	Yes	No
guarantee	Yes	No	Yes	No

As verbs, guarantee is a hypernym of insure; that is, guarantee is a word with a broader meaning than insure:

insure: protect by insurance
guarantee: stand behind and guarantee the quality, accuracy, or condition of

Other hypernyms of insure include warrant.

As verbs, insure and guarantee are synonyms defined as:

Other synonyms of insure include assure, ensure, secure.

insure (noun)	guarantee (noun)
	a written assurance that some product or service will be provided or will meet certain specifications
	an unconditional commitment that something will happen or that something is true
	a collateral agreement to answer for the debt of another in case that person defaults

insure (verb)	guarantee (verb)
be careful or certain to do something; make certain of something	give surety or assume responsibility
protect by insurance	promise to do or accomplish
make certain of	stand behind and guarantee the quality, accuracy, or condition of
take out insurance for	make certain of