Ability parking gets worse after crash (6)
I believe the answer is:
powers
'ability' is the definition.
(thesaurus)
'parking gets worse after crash' is the wordplay.
'parking' becomes 'p' (abbreviation on road signs).
'gets' is an insertion indicator.
'after crash' indicates anagramming the letters (I've seen 'after crashing' mean this (the original order crashes or breaks)).
'worse' with letters rearranged gives 'owers'.
'p' put within 'owers' is 'POWERS'.
(Other definitions for powers that I've seen before include "The ...... that be are people in authority" , "Supplies with energy" , "Countries in terms of their world influence" .)