Having downed last of grappa, using neat rum is thus! (10)
I believe the answer is:
nauseating
'having' is the definition.
The answer and definition can be both to do with perception as well as being present participle verbs.
Perhaps they are linked in a way I don't understand?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for nauseating that I've seen before include "Stomach-turning" , "arousing unpleasant feeling" , "Revolting" , "being hard to keep down" , "Loathsome" .)