Unsympathetic type, one committed to very firm course (9)
I believe the answer is:
sociopath
'unsympathetic type' is the definition.
'one committed to very firm course' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'very' could be 'so' (I've seen this in other clues) and 'so' is found within the answer.
'firm' could be 'co' (a firm is a company) and 'co' is located in the remaining letters.
'course' could be 'path' ('path' can be a synonym of 'course') and 'path' is located in the answer.
No letters remain.
This explanation may well be incorrect...
(Other definitions for sociopath that I've seen before include "dangerous individual" , "Psycho" , "One who's disturbed" , "Antisocial being" .)