Whisky uncapped - classy, extravagant (8)
I believe the answer is:
wasteful
'extravagant' is the definition.
(similar in meaning)
'whisky uncapped classy' is the wordplay.
'whisky' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
'uncapped' means to remove the first letter.
'classy' becomes 'tasteful' (I've seen this in another clue).
'tasteful' with its first letter taken off is 'asteful'.
'w'+'asteful'='WASTEFUL'
(Other definitions for wasteful that I've seen before include "Awful set (anag.)" , "Faults we consider being profligate" , "Extravagant" , "Prodigal" , "Uneconomical" .)