Muggy (adjective)

1. Uncomfortably warm and humid.
2. Stuffy or oppressive due to a combination of heat and humidity.

Origin:

18th century: of unknown origin.

Examples:

1. It was a muggy summer evening and he was sweating profusely.
2. The air was muggy and it was difficult to breathe.
3. The muggy weather made it difficult to sleep at night.
4. It was a muggy day and the heat was unbearable.
5. The humidity made the air muggy and difficult to breathe.