Ludicrous barrel blocking fluid haulage (9)
I believe the answer is:
laughable
'ludicrous' is the definition.
(I know that ludicrous can be written as laughable)
'barrel blocking fluid haulage' is the wordplay.
'barrel' becomes 'bl' (abbreviation).
'blocking' indicates putting letters inside (to block can mean to plug a gap in something).
'fluid' indicates an anagram.
'haulage' is an anagram of 'laughae'.
'bl' going within 'laughae' is 'LAUGHABLE'.
(Other definitions for laughable that I've seen before include "Ridiculous - make you chortle" , "comic" , "Ludicrous" , "Risible, ridiculous" , "Ridiculous, derisory" .)