I leave ridiculous organisation; it's farcical (9)
I believe the answer is:
ludicrous
'it's farcical' is the definition.
(synonyms)
'i leave ridiculous organisation' is the wordplay.
'leave' suggests deleting specific letters.
'organisation' indicates an anagram.
'ridiculous' with 'i' taken away is 'rdiculous'.
'rdiculous' anagrammed gives 'LUDICROUS'.
(Other definitions for ludicrous that I've seen before include "Utterly laughable" , "Farcical" , "Ridiculously foolish" , "Nonsensical" , "Risible" .)