Mighty impressive record in charge (4)
I believe the answer is:
epic
'mighty impressive' is the definition.
(epic means mighty or grand)
'record in charge' is the wordplay.
'record' becomes 'EP' (abbreviation for extended play record).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'ep'+'ic'='EPIC'
(Other definitions for epic that I've seen before include "Long poem set in nice picture" , "Long literary work about great events" , "Heroic, huge" , "Exodus, say" , "Long narrative poem telling of a hero's deeds" .)