Deny record distribution of mail (8)
I believe the answer is:
disclaim
'deny' is the definition.
(disclaiming is a kind of denying)
'record distribution of mail' is the wordplay.
'record' becomes 'disc' (synonyms).
'distribution of' is an anagram indicator.
'mail' with letters rearranged gives 'laim'.
'disc'+'laim'='DISCLAIM'
(Other definitions for disclaim that I've seen before include "Deny or relinquish" , "Forswear" , "Disown or deny, maybe responsibility" , "Renounce" , "Deny, refuse to acknowledge" .)