Is "frowned" upon an adjective or a verb? and how do we use it?
I know that we use frowned upon to describe something controversial, for example:
Having relationship between teachers and students is forbidden. It is frowned upon.
I would like to know whether "frowned" upon here is used as an adjective or a verb with passive voice?
Normally, which way do we use it?so does it mean that we normally use it as a verb in passive voice?