Daring to include this setter really is playful (8)
I believe the answer is:
gamesome
'playful' is the definition.
(I've seen this in another clue)
'daring to include this setter really' is the wordplay.
'daring' becomes 'game' (I can't justify this - if you can you should give a lot more credence to this answer).
'to include' indicates putting letters inside.
'this setter' becomes 'me' (person setting the crossword).
'really' becomes 'so' (both can mean 'extremely').
'me'+'so'='meso'
'game' placed around 'meso' is 'GAMESOME'.
'is' is the link.
Can you help me to learn more?
(Another definition for gamesome that I've seen is " Sportive".)