A rendition, ludicrously excessive (10)
I believe the answer is:
inordinate
'excessive' is the definition.
(I know that excessive can be written as inordinate)
'a rendition ludicrously' is the wordplay.
'ludicrously' is an anagram indicator (I've seen this in other clues).
'a'+'rendition'='arendition'
'arendition' with letters rearranged gives 'INORDINATE'.
(Other definitions for inordinate that I've seen before include "Unusually large" , "Excessive" , "disorderly" .)