快活
kuàihuó · HSK 5
cheerful
😄 快 = fast/quick + 活 = alive → quick-alive = lively, merry
快活 literally stacks 快 (quick, snappy) onto 活 (alive, living). A 'quick-alive' mood is a peppy, jaunty one — cheerful energy rather than calm contentment.
快 — heart radical 忄 + 夬 (phonetic)
快 is a semantic-phonetic compound. The heart radical 忄 carries the meaning, since the original sense referred to a feeling of pleasure or delight. The right side 夬 supplies the sound. The meaning later extended from 'pleased' to 'quick, fast', the dominant modern sense.
活 — water radical 氵 + tongue 舌
Originally a phono-semantic compound: 氵 (water) suggests flowing or liveliness, while 舌 (tongue) hints at the sound. Early forms depicted gushing water, conveying the idea of being lively or alive. The meaning broadened from 'flowing water' to 'living, alive, active.'