炎热
yánrè · HSK 7
scorching/blazing hot
🔥🥵 炎 = fire 火 stacked on fire 火 (double flame); 热 = hot — so doubly blazing hot
炎 literally doubles the fire radical 火 to mean flame/blaze, and 热 carries the plain sense of hot. Stack them and you get heat past the point of comfort: scorching, blazing weather.
热 — 执 zhí (phonetic) + 灬 fire radical
热 is a semantic-phonetic compound: the bottom 灬 (a variant of 火 'fire') gives the meaning of heat, while 执 on top supplies the sound. Originally written 熱, it depicted fire below a phonetic element, and the meaning naturally extended from physical heat to 'hot' weather and 'enthusiastic' feelings.