Run old repeat that's slammed (7)
I believe the answer is:
operate
'run' is the definition.
(I know that run can be written as operate)
'old repeat that's slammed' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'that's slammed' indicates an anagram.
'repeat' is an anagram of 'perate'.
'o'+'perate'='OPERATE'
(Other definitions for operate that I've seen before include "Carry on business" , "Perform as surgeon does" , "Control, run, a machine say" , "Work, function" , "man" .)