One large sound, not making sense (9)
I believe the answer is:
illogical
'sense' is the definition.
(I have seen 'lacking sense' mean 'illogical' so perhaps 'sense' could also mean 'illogical')
'one large sound not' is the wordplay.
'one' becomes 'i' (Roman numeral).
'large' becomes 'L' (eg in clothes sizes).
'sound not' becomes 'logical' (I've seen this in another clue. I am not sure about the 'not' bit.).
'i'+'l'+'logical'='ILLOGICAL'
'making' is the link.
Can you help me to learn more?
(Other definitions for illogical that I've seen before include "silly" , "making little sense" , "Lacking sound reasoning" , "not following" , "lacking sense" .)