Why “sweltering” is a great word
The state of being oppressively, humidly hot, causing physical discomfort and lassitude. From swelter (meaning "to faint or suffer from heat") and the present participle suffix -ing, first recorded in English in the 1560s. Unlike "scorching," which speaks of a dry, baking fire, or "tropical," which can suggest exotic fecundity, sweltering denotes a stagnant, cloying atmosphere that clings to the skin and burdens the lungs. It is the damp shirt fused to the small of your back, the slow, syruped pace of a city afternoon, and the dense, woolen air that makes each breath a conscious effort—a meteorological condition that feels, profoundly, like a moral verdict.