Incessant reader (8)
I believe the answer is:
bookworm
'incessant reader' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for bookworm that I've seen before include "Diligent student's" , "Person excessively fond of reading, like earth creature" , "One who enjoys reading" , "As keen reader" , "Incessant reader" .)