Study is over: that is, indefinitely adjourned (4,3)
I believe the answer is:
sine die
'indefinitely adjourned' is the definition.
(I've seen this before)
'study is over that is' is the wordplay.
'study' becomes 'den' (I've seen this before).
'over' shows that the letters should be reversed in order.
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'den'+'is'='denis'
'denis' backwards is 'sined'.
'sined'+'ie'='SINE DIE'
(Other definitions for sine die that I've seen before include "With no date agreed" , "Postponed indefinitely (L.)" , "For an indefinite period (Latin)" , "with no date for a restart" , "without a date" .)