From WordNet (r) 3.0 (2006):
hoar
adj 1: showing characteristics of age, especially having grey or
white hair; "whose beard with age is hoar"-Coleridge;
"nodded his hoary head" [syn: grey, gray, grey-
haired, gray-haired, grey-headed, gray-headed,
grizzly, hoar, hoary, white-haired]
n 1: ice crystals forming a white deposit (especially on objects
outside) [syn: frost, hoar, hoarfrost, rime]