fateful

1. ADJ If an action or a time when something happened is described as fateful, it is considered to have an important, and often very bad, effect on future events. 有重大影響的 (尤指産生負麪結果的)

It was a fateful decision, one which was to break the Government. 那是一項重大的決定，一個將使政府垮臺的決定。