Sign racket backfiring for Brezhnev, say? (6)
I believe the answer is:
leonid
'brezhnev say?' is the definition.
(Leonid Brezhnev)
'sign racket backfiring' is the wordplay.
'sign' becomes 'leo' (Leo is an example**).
'racket' becomes 'din' (I've seen this before).
'backfiring' says the letters should be written backwards.
'din' in reverse letter order is 'nid'.
'leo'+'nid'='LEONID'
'for' acts as a link.
(Other definitions for leonid that I've seen before include "- Brezhnev, Russian president" , "Small meteor" , "Brezhnev, for one" , "-- Brezhnev, former Soviet leader" , "bit of a shower" .)