hoar

(noun) ice crystals forming a white deposit (especially on objects outside). Synonyms: frost, hoarfrost, rime.

(adj) showing characteristics of age, especially having grey or white hair. Synonyms: grey, gray, grey-haired, gray-haired, grey-headed, gray-headed, grizzly, hoary, white-haired. Examples: "Whose beard with age is hoar"-coleridge." "Nodded his hoary head."