Pirate's grog (3)
I believe the answer is:
rum
'pirate's grog' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for rum that I've seen before include "Odd sort of spirit used in grog" , "Odd like drink distilled from molasses" , "Unusual" , "Strange drink from molasses" , "Funny" .)