Sharpen up some fortified wines (5)
I believe the answer is:
ports
'some fortified wines' is the definition.
(port is a kind of fortified wine)
'sharpen up' is the wordplay.
'sharpen' becomes 'strop' (stropping is a kind of sharpening).
'up' is a reversal indicator (in down clue: letters go upwards).
'strop' reversed gives 'PORTS'.
(Other definitions for ports that I've seen before include "Harbours" , "Places where people and merchandise enter or leave a country" .)