On detective, large bite (6)
I believe the answer is:
morsel
'bite' is the definition.
('morsel' can be a synonym of 'bite')
'on detective large' is the wordplay.
'on' means one lot of letters go next to another.
'detective' becomes 'morse' (I've seen this before).
'large' becomes 'l'.
'morse' next to 'l' is 'MORSEL'.
(Other definitions for morsel that I've seen before include "A tiny bit" , "Scrap, fragment" , "Tasty little piece" , "Tidbit" , "A scrap or shred of food" .)