Genuine, authentic (4)
I believe the answer is:
true
This clue is a double definition.
'genuine' is the first definition.
(I know that genuine can be written as true)
'authentic' is the second definition.
(I've seen this before)
(Other definitions for true that I've seen before include "Honest and straight" , "indeed" , "not showing 12 [DISHONESTY]" , "Consistent with fact" , "Genuine, actual" .)