Academic holding over preliminary text (5)
I believe the answer is:
proof
'preliminary text' is the definition.
(as in a proof copy)
'academic holding over' is the wordplay.
'academic' becomes 'prof' (short for professor).
'holding' means one lot of letters goes inside another.
'over' becomes 'o' (cricket abbreviation).
'prof' going around 'o' is 'PROOF'.
(Other definitions for proof that I've seen before include "Body of evidence" , "Author may have to check this" , "Incontrovertible evidence" , "paper for correcting" , "Test" .)