This kind of clue, by the sound of it, looks on a lower level (10)
I believe the answer is:
downstairs
'on a lower level' is the definition.
'this kind of clue by the sound of it looks' is the wordplay.
'this kind of clue' becomes 'down' (I can't explain this - if you can you should give a lot more credence to this answer).
'by the sound of it' indicates a 'sounds like' (homophone) clue.
'looks' becomes 'stares' (stare is a kind of look).
'stares' is a homophone of 'stairs'.
'down'+'stairs'='DOWNSTAIRS'
Can you help me to learn more?
(Other definitions for downstairs that I've seen before include "towards lower levels" , "On a lower floor" , "in the cellar?" , "On ground floor (or in basement)" .)