Grain alcohol (7)
I believe the answer is:
ethanol
'grain alcohol' is the definition.
(synonyms)
This is all the clue.
(Other definitions for ethanol that I've seen before include "Ethyl alcohol" , "spirit" , "Kind of alcohol - not hale (anag)" , "Intoxicant in wine, spirits, etc" , "Kind of alcohol found in Athlone" .)