glacial

1 :  suggestive of ice: as a :  extremely cold :  frigid <a glacial wind> b :  devoid of warmth and cordiality <a glacial handshake> c :  coldly imperturbable <maintained a glacial calm>

2 :  of a purity marked by the tendency to readily solidify in the form of ice-like crystals <glacial acetic acid>

3 a (1) :  of, relating to, or being any of those parts of geologic time from Precambrian onward when a much larger portion of the earth was covered by glaciers than at present (2) capitalized :  pleistocene b :  of, relating to, or produced by glaciers c :  suggestive of the very slow movement of glaciers <progress on the bill has been glacial>