Frozen spikes (7)
I believe the answer is:
icicles
'frozen spikes' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for icicles that I've seen before include "They hang by the wall (L.L.Lost)" , "'When ... hang by the wall / And Dick the shepherd blows his nail' (Shakespeare)" , "Frozen stalactites" , "Frozen drips" , "Pendent spears of frozen water (7)" .)