Cocaine hidden in shoe? It's malicious gossip (7)
I believe the answer is:
scandal
'malicious gossip' is the definition.
('scandal' can be a synonym of 'malicious gossip')
'cocaine hidden in shoe?' is the wordplay.
'cocaine' becomes 'c' (drugs abbreviation).
'hidden in' is an insertion indicator.
'shoe?' becomes 'sandal' (sandal is a kind of shoe).
'c' inserted into 'sandal' is 'SCANDAL'.
'it's' acts as a link.
(Other definitions for scandal that I've seen before include "Shocking thing" , "Malicious gossip" , "Public outrage; gossip" , "dirt" , "disgraceful behaviour" .)