Desk a chap left outside back of inn (9)
I believe the answer is:
davenport
'desk' is the definition.
(davenport is a kind of desk)
'a chap left outside back of inn' is the wordplay.
I cannot quite see how this works, but
'a' is found in the answer.
'chap' could be 'port' and 'port' is found within the answer.
This explanation may well be incorrect...
(Other definitions for davenport that I've seen before include "One who looks into the future" , "writing-desk" , "Drink for a hotel worker" .)