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 see 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 found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'of' is the 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" .)