Car manufacturer employs one that's oddly lacking ability (5)
I believe the answer is:
might
'ability' is the definition.
(thesaurus)
'car manufacturer employs one that's oddly lacking' is the wordplay.
'car manufacturer' becomes 'mg' (MG is a car manufacturer).
'employs' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'oddly lacking' means one should take alternating letters (letters in odd-numbered positions removed).
The alternate letters of 'that' are 'ht'.
'mg' placed around 'i' is 'mig'.
'mig'+'ht'='MIGHT'
(Other definitions for might that I've seen before include "is not unlikely to" , "What functions as an auxiliary" , "Strength - could possibly" , "Great power/strength" , "May, in the past" .)