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