Drone carrying an upturned book (5)
I believe the answer is:
nahum
'book' is the definition.
(I know that Nahum is a book)
'drone carrying an upturned' is the wordplay.
'drone' becomes 'hum' (drone can mean to make a humming sound).
'carrying' means one lot of letters go next to another (in a down clue, the bottom letters carry others).
'upturned' is a reversal indicator.
'an' backwards is 'na'.
'hum' after 'na' is 'NAHUM'.
(Other definitions for nahum that I've seen before include "Minor prophet" , "Destruction-of-Nineveh prophet" , "Old Hebrew prophet" , "OT book and prophet who foretold the fall of Nineveh" , "Hebrew prophet - Biblical book" .)