chastise, attack, defeat, destroy, conquer
討 centers on aggressive action to overcome an opponent: chastising, attacking, defeating, destroying, or conquering. The common thread is forceful confrontation aimed at subduing.
討 combines 言 (words) and 寸 (a hand with a tool, often associated with action or measurement). The combination suggests using words to direct or measure out punishment, leading to the idea of chastising or attacking.
Words (言) plus a hand holding a tool (寸) suggest using speech to command an attack or to measure out punishment. Imagine a general giving a speech before ordering the troops to strike.
For トウ, imagine a toe (トウ) being stepped on, prompting an angry verbal attack: toe -> トウ, and the words lead to chastisement.
consideration; examination; investigation; study; scrutiny; discussion; analysis; review
debate; discussion
subjugation (using military force); suppression; subduing
to attack; to destroy; to defeat; to conquer; to avenge
killing a would-be avenger
debate; discussion
cleaning up (enemy remnants); sweeping clean (of opponents); mopping up
attacking a fleeing enemy
death in battle; death on the battlefield
destroying; annihilating; eradicating
vengeance; revenge; retaliation
vengeance; revenge; retaliation
storming (e.g. an enemy's castle); attack; raid
tracking down and killing; punitive expedition
surprise attack; sneak attack; foul play
execution (on the command of a feudal lord)
to avenge (someone) by striking down their killer
debate between party leaders (in the Japanese Diet)
public debate; open discussion
open forum