消す
けす · kesu · JLPT N5 · verb-godan
to turn off power
🧽 消 = water 氵 + 肖 (shrink): water wears it away until it is gone
The kanji 消 pairs the water radical with 肖, a part that carries the idea of dwindling. Kesu is the transitive partner of kieru (to vanish): you make something vanish, whether chalk marks, a file, or a light. Sound hook: K.O. it, kesu.
消 — water 氵 + 肖 (phonetic)
消 is a semantic-phonetic compound: the water radical 氵 indicates the meaning, while 肖 (xiào) supplies the sound. It originally described water dwindling or melting away, and from there extended to the modern senses of vanishing, dissolving, and dispelling.