Before last part, raise drink (8)
I believe the answer is:
cocktail
'drink' is the definition.
(cocktail is a kind of drink)
'before last part raise' is the wordplay.
'before' means one lot of letters go next to another.
'last part' becomes 'tail' (tail is a kind of part. I am not sure about the 'last' bit.**).
'raise' becomes 'cock' (eg a dog can cock his leg).
'tail' after 'cock' is 'COCKTAIL'.
Can you help me to learn more?
(Other definitions for cocktail that I've seen before include "Harvey Wallbanger, for example" , "old-fashioned in America" , "dish with prawn" , "Manhattan, for example" , "Possibly old-fashioned" .)