光滑
guāng huá · HSK 7
smooth
🪞 光 (shiny/light) + 滑 (slippery) = a shiny, slippery surface, hence glossy and smooth
滑 also shows up in 滑冰 (ice-skating) and 滑梯 (slide), so it carries the slippery-smooth sense. Pair that with 光 meaning shiny or bright, and 光滑 lands on glossy, sleek, smooth.
光 — fire 火 (top) + person 儿 (bottom)
Originally a pictograph of a person with fire above their head, depicting a torchbearer or the radiance from a flame. The character evolved to mean 'light' or 'brightness' in general, and by extension 'glory' and 'to shine.' The modern top component is a stylized form of 火 (fire).
滑 — water radical 氵 + bone 骨
A semantic-phonetic compound: 氵 (water) gives the meaning of slipperiness, while 骨 (bone) supplies the sound. The original sense was 'slippery,' as water makes surfaces hard to grip, and it later extended to 'smooth' and figuratively 'cunning' or 'sly.'