gray-headed vs gray-haired

gray-headed and gray-haired both are adjectives.

Word	Noun	Adjective	Verb	Adverb
gray-headed	No	Yes	No	No
gray-haired	No	Yes	No	No

As adjectives, gray-headed and gray-haired are synonyms defined as:

gray-headed and gray-haired: showing characteristics of age, especially having grey or white hair

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

gray-headed (adjective)	gray-haired (adjective)
showing characteristics of age, especially having grey or white hair	showing characteristics of age, especially having grey or white hair