Too smart for each delivery (7)
I believe the answer is:
flipper
'delivery' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'too smart for each' is the wordplay.
'too smart' becomes 'flip' (I am not sure about this - if you are sure you should believe this answer much more).
'for each' becomes 'per' (per person).
'flip'+'per'='FLIPPER'
Can you help me to learn more?
(Other definitions for flipper that I've seen before include "Limb used for swimming" , "Limb of a seal" , "Aquatic animal's fin" , "Flat broad limb of aquatic animals" , "More frivolous" .)