Freeze over (3)
(Other definitions for ice that I've seen before include "dessert" , "Form of water" , "It's cold and slippy" , "Cold demeanour" , "Rocks on which drink is served?" .)
'freeze over' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ice up that I've seen before include "become frozen" , "Completely freeze" , "get coat" .)