Tell tale activity (7)
I believe the answer is:
archery
'tell tale activity' is the definition.
(I've seen this in another clue)
'tell tale activity' is the wordplay.
'tell' becomes 'archer' (I've seen this before).
'tale activity' becomes 'y' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'archer'+'y'='ARCHERY'
Can you help me to learn more?
(Other definitions for archery that I've seen before include "Arrow-shooting" , "The sport of shooting arrows with a bow" , "Sport of the bowman" , "The sport of bowmen" , "Target sport - Olympic event in from 1900-08, in 1920 and since 1972" .)