Permit to hire (3)
I believe the answer is:
let
I believe this clue is a double definition.
'permit to' is the first definition.
(I've seen this before)
'hire' is the second definition.
(I've seen this in another clue)
(Other definitions for let that I've seen before include "Service that must be repeated" , "Allow; permit" , "Allow; leased" , "Allow the obstruction" , "Allow on the tennis court" .)