Son consuming lean cheese (7)
I believe the answer is:
stilton
'cheese' is the definition.
(stilton is a cheese)
'son consuming lean' is the wordplay.
'consuming' means one lot of letters goes inside another.
'lean' becomes 'tilt' (synonyms).
'son' placed around 'tilt' is 'STILTON'.
(Other definitions for stilton that I've seen before include "Cheese named after Cambridgeshire town" , "Blue 4 across" , "English cheese, usually veined" , "19 cheese" , "Dairy product" .)