Learning game in publication (9)
I believe the answer is:
erudition
'learning' is the definition.
('erudition' can be a synonym of 'learning')
'game in publication' is the wordplay.
'game' becomes 'ru' (rugby union).
'in' means one lot of letters goes inside another.
'publication' becomes 'edition' (edition is a kind of publication**).
'ru' put within 'edition' is 'ERUDITION'.
(Other definitions for erudition that I've seen before include "Knowledge, learning" , "profound scholarly knowledge" , "Learnedness, scholarship" , "being widely read" , "Great learning" .)