Petty official patient man throws out (9)
I believe the answer is:
jobsworth
'petty official' is the definition.
(I've seen this before)
'patient man throws out' is the wordplay.
'patient man' becomes 'Job' (biblical figure famous for patience).
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'throws' anagrammed gives 'sworth'.
'job'+'sworth'='JOBSWORTH'
(Other definitions for jobsworth that I've seen before include "Petty bureaucrat" , "Official who upholds petty rules" , "Petty rules upholder" , "A stickler for rules" .)