Lumpy hooter's terribly loud inside (8)
I believe the answer is:
nodulose
'lumpy' is the definition.
(I've seen this before)
'hooter's terribly loud inside' is the wordplay.
'hooter' becomes 'nose' (I've seen this before).
'terribly' indicates an anagram.
'inside' means one lot of letters goes inside another.
'loud' is an anagram of 'dulo'.
'nose' enclosing 'dulo' is 'NODULOSE'.
(Other definitions for nodulose that I've seen before include "with knobs on" , "Like a small swelling" , "Lumpy" .)