Learned study in wordplay, say, rejected (6,2)
I believe the answer is:
genned up
'learned' is the definition.
(to gen up on a topic is to learn about it)
'study in wordplay say rejected' is the wordplay.
'study' becomes 'den' (term for a study or office).
'in' indicates putting letters inside.
'wordplay' becomes 'pun' (synonyms).
'say' becomes 'eg' (both can mean for example).
'rejected' says the letters should be written in reverse.
'pun'+'eg'='puneg'
'den' put into 'puneg' is 'pudenneg'.
'pudenneg' backwards is 'GENNED UP'.
(Another definition for genned up that I've seen is " Fully conversant".)