In the company of haggard introvert (9)
I believe the answer is:
withdrawn
'introvert' is the definition.
'in the company of haggard' is the wordplay.
'in the company of' becomes 'with' (I've seen this before).
'haggard' becomes 'drawn' (synonyms).
'with'+'drawn'='WITHDRAWN'
(Other definitions for withdrawn that I've seen before include "Quiet" , "Shy, reserved" , "Pulled out of" , "Private" , "Rather shy" .)