This is the 2405th most frequent Korean word.
금지하는
"Prohibiting" or "forbidding."
The word '금지하는' is used here as an adjective to describe '장소' (place), indicating that the place prohibits smoking.
여기는 흡연을 금지하는 장소입니다.
This is a place where smoking is prohibited.
In this sentence, '금지하는' is used in the form of a relative clause describing the tendency ('경향'), specifying the action being forbidden.
그는 친구가 너무 자주 게임을 하는 것을 금지하는 경향이 있어요.
He tends to forbid his friend from playing games too often.
Here, '금지하는' functions within a clause to describe a set of rules ('규정') that include the act of prohibition of certain activities.