Absolutely accurate or correct (5)
I believe the answer is:
exact
This clue is a double definition.
'absolutely accurate' is the first definition.
(I've seen this before)
'correct' is the second definition.
(similar in meaning)
(Other definitions for exact that I've seen before include "Rigorous" , "on the money" , "Demand and obtain" , "Absolutely right" , "Precisely correct" .)