Icicle former (4)
I believe the answer is:
drip
'icicle former' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for drip that I've seen before include "Ineffectual person; hospital apparatus" , "Ineffectual type" , "As a tear appears" , "Hospital device; weak person" , "Leak slowly" .)