Definition
to retreat swiftly from someone or something, often due to fear.
（通常指因為害怕）退後；撤退
Faced with the sudden danger, they fell back swiftly without a second thought.
面對突如其來的危險，他們毫不猶豫地迅速撤退。
Seeing the large wild animal, they instinctively fell back.
看到那隻巨大的野生動物，他們本能地退後了。
She fell back in fright due to her fear.
她因為恐懼而驚慌地退後了。
When an army withdraws to avoid confrontation with an adversary.
（部隊）向後撤退
When faced with a formidable enemy, the troops decided to fall back to protect themselves.
面對強大的敵人，部隊決定向後撤退以保護自己。
To avoid confrontation, the commander ordered the army to fall back.
為了避免衝突，指揮官下令部隊向後撤退。
After the fierce battle, the troops had to fall back.
激烈的戰鬥過後，部隊不得不向後撤退。