Shipping hazard (7)
I believe the answer is:
iceberg
'shipping hazard' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for iceberg that I've seen before include "main danger" , "Broken piece of a glacier" , "Polar shipping hazard" , "Type of floe" , "(Frozen?) type of lettuce" .)