Gossip about a mad character (7)
I believe the answer is:
chatter
'gossip' is the definition.
(I know that gossip can be written as chatter)
'about a mad character' is the wordplay.
'about' becomes 'c' (abbreviation for circa).
'a mad character' becomes 'hatter' (Alice In Wonderland).
'c'+'hatter'='CHATTER'
(Other definitions for chatter that I've seen before include "Talk incessantly" , "Prattle" , "Idle talk" , "Talk informally" , "Noisy talk" .)