A rendition becoming excessive (10)
I believe the answer is:
inordinate
'excessive' is the definition.
('inordinate' can be a synonym of 'excessive')
'a rendition becoming' is the wordplay.
'becoming' indicates an anagram.
'a'+'rendition'='arendition'
'arendition' anagrammed gives 'INORDINATE'.
(Other definitions for inordinate that I've seen before include "Unusually large" , "disorderly" , "Excessive" .)