Etymology: (bef. 900; ME hor, OE hār, c. OS, OHG hēr old, ON hārr gray with age)
Definition of 'hoar'
Princeton's WordNet
1. (adj)frost, hoar, hoarfrost, rime ice crystals forming a white deposit (especially on objects outside)
2. (adj)grey, gray, grey-haired, gray-haired, grey-headed, gray-headed, grizzly, hoar, hoary, white-haired showing characteristics of age, especially having grey or white hair "whose beard with age is hoar"-Coleridge; "nodded his hoary head"
Definitions of hoar 
