Grant is let in (5)
I believe the answer is:
admit
I believe this clue is a double definition.
'grant' is the first definition.
(I've seen this in another clue)
'is let in' is the second definition.
(I've seen this before)
(Other definitions for admit that I've seen before include "Allow to enter; own up" , "receive" , "Accept" , "Confess - acknowledge" , "Take on" .)