Answer:
The prefix is ben-.
The prefix ben- means well or good.
The word "benign" means gentle or kind.
Explanation:
The word benign comes from the Latin words "bene" and "genus". Bene, that has become the prefix "ben-" to many other words (such as benevolent and benefactor), means well or good. Genus means born. Thus, something that is benign is something that is good, gentle.
The prefix that represents the opposite meaning of ben- is mal-. The opposite of benign is malign.
