Collar uneven, by the sound of it? (4)
I believe the answer is:
ruff
'collar' is the definition.
(I know that ruff is a type of collar)
'uneven by the sound of it?' is the wordplay.
'uneven' becomes 'rough' (associated in meaning).
'by the sound of it?' indicates a 'sounds like' (homophone) clue.
'rough' is a homophone of 'RUFF'.
(Other definitions for ruff that I've seen before include "Frilly collar" , "Male sandpiper" , "Win a trick by using a trump" , "Starched frill; fish" , "Starched, frilled collar" .)