Pronunciation: (frô'stē, fros'tē),[key] —adj.,frost•i•er, frost•i•est. 1. characterized by or producing frost; freezing; very cold: frosty weather. 2. consisting of or covered with a frost: frosty designs on the windows; an avenue of frosty trees. 3. lacking warmth of feeling; unfriendly: Their frosty greeting puzzled us. 4. resembling frost; white or gray: a wedding dress of frosty satin. 5. of or characteristic of old age: a frosty brow.