Stubborn old boy, say, outside home (9)
I believe the answer is:
obstinate
'stubborn' is the definition.
(I know that stubborn can be written as obstinate)
'old boy say outside home' is the wordplay.
I cannot really understand how this works, but
'old' could be 'o' (common abbreviation eg in OE for Old English) and 'o' is found in the answer.
'boy' could be 'nate' and 'nate' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for obstinate that I've seen before include "headstrong" , "Stubborn, obdurate" , "Female bird" , "such as a mule" , "Mulish" .)