Point after heading off penalty is useless (5)
I believe the answer is:
inept
'useless' is the definition.
(thesaurus)
'point after heading off penalty' is the wordplay.
'point' becomes 'pt'.
'after' is a charade indicator (letters next to each other).
'heading off' means to remove the first letter.
'penalty' becomes 'fine' (fine is a kind of penalty).
'fine' with its initial letter removed is 'ine'.
'pt' put after 'ine' is 'INEPT'.
'is' acts as a link.
(Other definitions for inept that I've seen before include "rubbish" , "pointless" , "Awkward, showing no skill" , "Ham-fisted" , "Lacking any competence" .)