Stubborn old boys with money to eat out (9)
I believe the answer is:
obstinate
'stubborn' is the definition.
('obstinate' can be a synonym of 'stubborn')
'old boys with money to eat out' is the wordplay.
'old boys' becomes 'obs' (I've seen this in other clues).
'with' says to put letters next to each other.
'money' becomes 'tin' (I've seen this before**).
'to' means one lot of letters go next to another.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'eat' anagrammed gives 'ate'.
'obs'+'tin'+'ate'='OBSTINATE'
(Other definitions for obstinate that I've seen before include "such as a mule" , "Firm" , "headstrong" , "Blindly stubborn" , "Pig-headed" .)