Greet; frozen rain (4)
I believe the answer is:
hail
This clue is a double definition.
'greet' is the first definition.
(I know that greet is a is a more specific form of the action of hail)
'frozen rain' is the second definition.
(I've seen this in another clue)
(Other definitions for hail that I've seen before include "Greet - precipitation" , "Precipitation - old greeting" , "a drop of the hard stuff?" , "volley" , "An old Roman salute as to Caesar" .)