Frosts (4)
I believe the answer is:
ices
'frosts' is the definition.
('ice' can be a synonym of 'frost')
This is all the clue.
(Other definitions for ices that I've seen before include "Kills (slang) - sweets" , "Freezes" , "Frozen desserts" , "Cones etc" , "Decorates cakes with frosting" .)