Don't be too greedy to consume duck! (5)
I believe the answer is:
avoid
'duck' is the definition.
(duck can mean to avoid)
'don't be too greedy to consume' is the wordplay.
'don't be too' becomes 'o' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'greedy' becomes 'avid' (synonyms).
'to consume' means one lot of letters goes inside another.
'o' going into 'avid' is 'AVOID'.
Can you help me to learn more?
(Other definitions for avoid that I've seen before include "Shirk" , "Bypass" , "Desist" , "Refrain from (something)" , "Eschew" .)