A primary verb meaning to throw, hurl, cast, or place. It covers physical throwing (stones, nets, seeds), placing or putting (money into the treasury, leaven into dough), and eschatological casting (Satan cast into the lake of fire). It forms numerous compounds: ekballō (cast out), periballō (clothe, wrap around), metaballō (change).
The NT uses ballō at critical junctures of judgment and faith. Jesus cast out (exeballen) demons and moneychangers. The fishermen cast nets at Jesus' command (Luke 5:4; John 21:6) — an act of trust. The poor widow cast her two mites into the treasury, and Jesus declared she gave more than all (Mark 12:41-44). In the eschaton, the devil, death, and hades are cast into the lake of fire (Rev 20:10-14). The violent imagery of casting/throwing conveys decisive, irreversible action — whether judgment or trust. Faith itself is a kind of ballō: casting your care upon Him (1 Pet 5:7 uses a different verb but the concept is parallel), throwing everything on God's faithfulness.