This is the 9557th most frequent Japanese word.
締め出さ
"締め出す" means "to shut out" or "to exclude."
In this sentence, '締め出しました' means 'shut out' or 'excluded', used in the context of preventing someone from entering a space deliberately.
彼を会議室から締め出しました。
He was shut out of the meeting room.
Here, '締め出して' conveys the concept of obstructing or keeping something from view, metaphorically shutting out the sight of the mountain by the fog.
霧が山の景色を締め出してしまった。
The fog blocked the view of the mountains.
In this case, '締め出す' is used to refer to the action of excluding or barring competitors from participating in a market space.