Some scoff “I won’t pipe down” (4)
I believe the answer is:
nosh
'some scoff' is the definition.
(I've seen this before)
'i won't pipe down' is the wordplay.
'i won't' becomes 'no' (refusal).
'pipe down' becomes 'sh' (both can mean 'be quiet').
'no'+'sh'='NOSH'
(Other definitions for nosh that I've seen before include "'Food, grub (4)'" , "eating this?" , "chow" , "Scoff" , "(Eat) a snack" .)