Frozen over (4)
'frozen over' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for iced that I've seen before include "Covered with flavoured sugar topping" , "Decorated; killed" , "Decorated (a cake)" , "What cake might be" , "found thus in freezer?" .)
(Other definitions for icebound that I've seen before include "trapped by wintry conditions" , "(Of ship) trapped by frozen water" , "Locked in by frozen water" , "Trapped by frozen sea" , "(Arctic ship) stuck for winter" .)