When there is a lot of moisture in the air, it is humid out. The air in a rain forest is humid, the air in a desert is dry.
People like to say that it’s not the heat that bothers them, it’s the humidity. They say this because when it is humid, or when there is a lot of water in the air, the heat feels hotter. It also makes wavy hair frizzy and straight hair limp. Air that is cold and moist is called damp, so when people talk about humid air, think tropical, as that’s usually how the word is meant.
containing or characterized by a great deal of water vapor“humid air”“humid weather”
covered or soaked with a liquid such as water