Humidity is a measure of the amount of water vapor in the air. It is often expressed as a percentage, with higher values indicating more MOISTURE in the air. The term 'MOISTURE' (8 letters) is used to describe the presence of water vapor in the air, while 'WETNESS' (7 letters) is used to describe the feeling of DAMPNESS or WETNESS. 'DAMP' (4 letters) is used to describe a slightly wet surface, and 'DAMPNESS' (8 letters) is used to describe a more intense level of WETNESS. All of these terms are related to humidity, which is the measure of the amount of water vapor in the air.