Frosts a cake (4)
I believe the answer is:
ices
'frosts a cake' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ices that I've seen before include "Kills (slang) - sweets" , "Frozen desserts" , "Frozen sweets" , "Decorates cake with sugar topping" , "summer refreshment" .)