hoary vs hoar

hoary is not a noun while hoar is a noun.

Word	Noun	Adjective	Verb	Adverb
hoary	No	Yes	No	No
hoar	Yes	Yes	No	No

As adjectives, hoary and hoar are synonyms defined as:

hoary and hoar: showing characteristics of age, especially having grey or white hair

Other synonyms of hoary include gray-haired, gray-headed, gray, grey-haired, grey-headed, grey, grizzly, white-haired.

hoary (noun)	hoar (noun)
	ice crystals forming a white deposit (especially on objects outside)

hoary (adjective)	hoar (adjective)
covered with fine whitish hairs or down	showing characteristics of age, especially having grey or white hair
ancient
showing characteristics of age, especially having grey or white hair