落ち込む
おちこむ · ochikomu · JLPT N1 · verb-godan
to get depressed
🌧️ 落 (fall) + 込む (sink into) = falling down into a low, gloomy state
落ち = drop, 込む = go inside, sink in. Together: your mood drops and sinks inward, like a heavy rain cloud pressing down.
落 — grass radical 艹 + 洛 (water 氵 + 各)
Originally written with the grass radical 艹 over 洛, depicting leaves falling from plants. 洛 serves as the phonetic component (giving the luò sound) while 艹 supplies the meaning of vegetation. The sense extended from 'leaves falling' to the general meaning of falling, dropping, or settling down.