Permit to hire (3)
I believe the answer is:
let
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 other clues)
(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" .)