Jasper is not part of practical jokes in Manhattan? (8)
I believe the answer is:
cocktail
'manhattan?' is the definition.
(manhattan is a kind of cocktail)
'jasper is not part of practical jokes' is the wordplay.
I cannot quite understand how this works, but
'part' could be 'tail' (tail is a kind of part) and 'tail' is present in the answer.
'of' could be 'o' and 'o' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'in' acts as a link.
Can you help me to learn more?
(Other definitions for cocktail that I've seen before include "Mixed beverage" , "Possibly old-fashioned" , "snowball?" , "Screwdriver, for example" , "Manhattan, for example" .)