One in trite part ruined performance (14)
I believe the answer is:
interpretation
'performance' is the definition.
(I know that interpretation is a type of performance)
'one in trite part ruined' is the wordplay.
'ruined' indicates anagramming the letters.
'one'+'in'+'trite'+'part'='oneintritepart'
'oneintritepart' is an anagram of 'INTERPRETATION'.
(Other definitions for interpretation that I've seen before include "Individual delivery of a dramatic role" , "Analysis" , "Way of explaining" .)