Guilty copper competent to hold record (8)
I believe the answer is:
culpable
'guilty' is the definition.
(similar in meaning)
'copper competent to hold record' is the wordplay.
'copper' becomes 'cu' (chemical symbol).
'competent' becomes 'able' (similar in meaning).
'to hold' indicates putting letters inside.
'record' becomes 'L-P' (abbreviation for long play record).
'cu'+'able'='cuable'
'cuable' going around 'lp' is 'CULPABLE'.
(Other definitions for culpable that I've seen before include "Blameworthy, censurable" , "Criminally responsible" , "Answerable" , "Guilty" , "Proboscis" .)