Make fun of a fairly quiet twerp going round (7)
I believe the answer is:
lampoon
'make fun of' is the definition.
(I've seen this before)
'a fairly quiet twerp going round' is the wordplay.
'fairly quiet' becomes 'mp' (musical abbreviation for 'mezzo piano', half soft).
'twerp' becomes 'loon'.
'going round' is an insertion indicator.
'a'+'mp'='amp'
'amp' put within 'loon' is 'LAMPOON'.
(Other definitions for lampoon that I've seen before include "Ridicule with satire" , "Mock" , "send-up" , "joke" , "Personal satire" .)