Reason, discernment (5)
I believe the answer is:
sense
This clue is a double definition.
'reason' is the first definition.
(I've seen this in another clue)
'discernment' is the second definition.
(I know that sense is a type of discernment)
(Other definitions for sense that I've seen before include "Meaning of a word or expression" , "Get an impression" , "Divine" , "reasonable" , "Perceptual faculty" .)