WordNet sense 1 (ice crystals forming a white deposit (especially on objects outside)):

hoarfrost, rime, hoar

WordNet sense 2 (the formation of frost or ice on a surface):

icing

WordNet sense 3 (weather cold enough to cause freezing):

freeze

WordNet sense 4 (United States poet famous for his lyrical poems on country life in New England (1874-1963)):

Robert Frost, Robert Lee Frost

WordNet sense 5 (decorate with frosting):

ice