Self-detonation or self-destruction (e.g., a suicide bombing); also used figuratively for actions that ruin one's own cause.
テロリストが自爆して多数の負傷者が出た。
A terrorist detonated himself and many people were injured.
会議で不用意な発言をして彼は自爆してしまった。
He made an ill-advised remark in the meeting and essentially sabotaged himself.
ゲームで敵の爆弾にぶつかって自爆した。
I ran into an enemy bomb in the game and blew myself up.