Caught leaving additives in drink (6)
I believe the answer is:
coffee
'drink' is the definition.
(coffee is a kind of drink)
'caught leaving additives' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'leaving' becomes 'off' (as in 'I'm off').
'additives' becomes 'ee' (I am not sure about this - if you are sure you should believe this answer much more).
'c'+'off'+'ee'='COFFEE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for coffee that I've seen before include "Popular bean drink, maybe instant" , "Popular drink made from ground beans" , "Common drink" , "Shrub; drink" , "Hot drink" .)