Assail with snowballs (4)
I believe the answer is:
pelt
'assail with snowballs' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pelt that I've seen before include "Animal skin with hair still on it" , "Skin; run fast" , "Throw - animal skin" , "Run fast - hide - pepper" , "Pour; hide" .)