Give the go-ahead for patent (5)
I believe the answer is:
clear
'for patent' is the definition.
(synonyms)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for clear that I've seen before include "Easy to see or understand" , "Open; not cloudy" , "Bright" , "Transparent - free of obstruction" , "Obvious; jump over" .)