Does he start batting cannily? (6)
I believe the answer is:
opener
'does he' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'start batting cannily?' is the wordplay.
'start' becomes 'open' (opening is a kind of starting).
'batting cannily?' becomes 'er' (I can't explain this - if you can you should give a lot more credence to this answer).
'open'+'er'='OPENER'
Can you help me to learn more?
(Other definitions for opener that I've seen before include "In cricket, a batsman who plays the first ball of an innings" , "Key -- one of two batsman in a side" , "A key or a bottle top remover" , "player, first to bat" , "No.1 or No.2 bat" .)