Drink to me and nobody else! (4)
I believe the answer is:
only
'else' is the definition.
Both the definition and answer are adjectives. Perhaps there's an association between them I don't understand?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for only that I've seen before include "Simply" , "Existing alone with no other, perhaps a child" , "Solely, lone" , "Single, solitary" , "Merely; single" .)