to knock (someone) down; to floor; to beat up
to deal a devastating blow (from which one cannot recover); to devastate (emotionally); to crush; to overwhelm; to defeat resoundingly; to give (an opponent) a drubbing
彼女の冷たい一言が彼を打ちのめして立ち直れなくした。
Her cold remark knocked him flat and he couldn't recover.
批判的な言葉が彼を打ちのめした。
The harsh words knocked him flat.
試合でチームが相手を完膚なきまでに打ちのめす展開となった。
The game turned into a complete rout as the team battered the opponent mercilessly.