放り込む
ほうりこむ · hourikomu · JLPT N1 · noun
to throw into
🗑️ 放り込む = 放る (throw) + 込む (go into): throw it in, so 'throw into'
込む means to go or push into a space, as in 書き込む (write in). Add 放る (throw) and you get throw-into, the verb for tossing something into a bin.
放 — 方 (square/phonetic) + 攵 (rap/strike radical)
放 is a semantic-phonetic compound: 方 supplies the sound and 攵 (a hand holding a stick) supplies the meaning of striking or driving away. The original sense was to banish or drive out, which broadened over time to 'release', 'let go', and 'put down'.