Revealing unskilfulness in record time (5)
I believe the answer is:
inept
'revealing unskilfulness' is the definition.
(inept means showing a lack of skill)
'in record time' is the wordplay.
'record' becomes 'EP' (abbreviation for extended play record).
'time' becomes 't' (abbreviation).
'in'+'ep'+'t'='INEPT'
(Other definitions for inept that I've seen before include "Unskilful, awkward" , "Clumsy, bumbling" , "Cack-handed" , "Lousy" , "Maladroit" .)