闷热 (mēn rè): sultry; sultriness; hot and stuffy; stifling hot

On a summer afternoon, the classroom was sultry and stuffy, and the students were all sweating profusely, constantly fanning themselves.

The weather forecast says it will be sultry today with high humidity; after walking just a few steps outside, you feel like you can't breathe.

Before the rain, the air was sultry and uncomfortable, and even the cicadas in the trees were chirping louder than usual.

Even though the air conditioner was on, the room was still sultry because the window wasn't closed and all the humidity from outside came in.