Potion; current (7)
I believe the answer is:
draught
This clue is a double definition.
'potion' is the first definition.
(thesaurus)
'current' is the second definition.
(a draught is a current of air)
(Other definitions for draught that I've seen before include "Indoor breeze" , "Slug" , "Dose of medicine" , "intake" , "Depth of a ship in the water" .)