Corny things in fodder for gossip (7)
I believe the answer is:
hearsay
'for gossip' is the definition.
(hearsay is a kind of gossip)
'corny things in fodder' is the wordplay.
'corny things' becomes 'ears' (an ear can refer to a piece of corn).
'in' means one lot of letters goes inside another.
'fodder' becomes 'hay' (hay is a kind of fodder).
'ears' placed within 'hay' is 'HEARSAY'.
(Other definitions for hearsay that I've seen before include "Testimony not based on direct knowledge" , "Gossip passed around by word of mouth" , "Common talk" , "Gossip or idle talk - it's not evidence" , "Rumour or gossip - inadmissible as evidence" .)