Hide bay rum unfinished before start of prohibition (5,2)
I believe the answer is:
cover up
'hide' is the definition.
(covering up is a kind of hiding)
'bay rum unfinished before start of prohibition' is the wordplay.
'bay' becomes 'cove' (I've seen this before).
'unfinished' means to remove the last letter.
'before' says to put letters next to each other.
'start of' says to take the initial letters.
The first letter of 'prohibition' is 'p'.
'rum' with its final letter taken away is 'ru'.
'cove'+'ru'+'p'='COVER-UP'
(Other definitions for cover up that I've seen before include "Attempt at concealment" , "whitewash" , "Withhold information" , "Conceal" , "cost of insurance has risen" .)