落す
おとす · otosu · JLPT N4 · verb-godan
to drop
🍂 otosu: Oh, toss! You let it drop, and now it is lost.
落 is the fall character (as in 落ちる ochiru, to fall). 落とす otosu is its transitive partner: you make something fall. Drop a wallet and it is gone, so the same verb also means to lose.
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.