Optimistic of swilling gin, perhaps, at the dance (6)
I believe the answer is:
hoping
'optimistic' is the definition.
(I've seen this in another clue)
'swilling gin perhaps at the dance' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'gin' is 'ing' which is present in the answer.
'dance' could be 'hop' (hop is a kind of dance) and 'hop' is present in the answer.
No letters remain.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for hoping that I've seen before include "Expecting and wishing" , "Trusting, expecting" , "Desiring with an expectation of success" , "Having wish or desire for" .)