Nothing for party to do but to launch by-product (8)
I believe the answer is:
offshoot
'by-product' is the definition.
(thesaurus)
'nothing for party to do but to launch' is the wordplay.
I cannot quite understand how this works, but
'nothing' could be 'o' (looks like zero - 0) and 'o' is present in the answer.
'party' could be 'ff' (I've seen this in other clues) and 'ff' is found in the answer.
'launch' could be 'shoot' (shoot is a kind of launch) and 'shoot' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for offshoot that I've seen before include "Side growth" , "Business subdivision, say" , "Sucker" , "Branch attached to the main stem" , "Something developing from another" .)