frost (n.) Look up frost at Dictionary.com
Old English forst, frost "a freezing, becoming frozen, extreme cold," from Proto-Germanic *frusta- (cognates: Old Saxon, Old Frisian, Old High German frost, Middle Dutch and Dutch vorst), related to freosan "to freeze," from PIE *preus- "to freeze; burn" (see freeze (v.)). Both forms of the word were common in English till late 15c.; the triumph of frost may be due to its similarity to the forms in other Germanic languages.
frost (v.) Look up frost at Dictionary.com
1630s, from frost (n.). Related: Frosted; frosting.