Greenlights (3)
'greenlights' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Another definition for oks that I've seen is " Passes".)
(Other definitions for okays that I've seen before include "Authorises" , "Sanctions" , "Gives the thumbs up" , "Agrees" , "Gives the go-ahead" .)