Make a stink about showbiz magazine's twaddle (5)
I believe the answer is:
hokum
'twaddle' is the definition.
(I know that twaddle can be written as hokum)
'make a stink about showbiz magazine's' is the wordplay.
'make a stink' becomes 'hum' (hum can mean to smell).
'about' means one lot of letters goes inside another.
'showbiz magazine' becomes 'OK' (OK! is a celebrity magazine).
'hum' going around 'ok' is 'HOKUM'.
(Other definitions for hokum that I've seen before include "Nonsense (colloq.)" , "Rubbish" , "Bunk" , "Sentimental stuff in play or film, nonsense" , "Be extremely good (at activity)" .)