This is the 623rd most frequent Korean word.
남성이
"남성이" means "man" or "male" in English when referring to the subject in a sentence.
Here, '남성이' indicates the subject (a man) of the action 'crossed the bridge'.
남성이 다리를 건넜습니다.
A man crossed the bridge.
Here, '남성이' emphasizes the subject (a man) in the context of the movie's protagonist.
이 영화는 남성이 주인공입니다.
The protagonist of this movie is a man.
Here, '남성이' functions as the subject (a man) for the action of taking on roles.