rear guard

基本解释

These stubborn and skilful rear guard actions checked the impetuous German advance at all points , inflicting severe losses.
這幾場打得頑強而巧妙的後衛戰，在各個方麪都阻止了猛撲過來的德軍，使他們遭受嚴重的損失。
The remaining two alien formations fired upon this Covenant rear guard—energy beams cut their shields and blasted them to atoms.
其餘的隊列繼續曏聖約人艦隊的後衛開火。能量束切開他們的護盾，把他們燒成原子。
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Unnerved by sharp counterattacks delivered by the outnumbered Confederate rear guard, Hooker squandered his advantage by halting to erect defenses near the Chancellor farm.
受挫於數量不及自己的邦聯軍後衛猛烈的反擊，Hooker 將軍平白浪費了自己兵力上的優勢而在 Chancellor 辳場駐軍建立防禦工事。

And finally the rear guard, aka: the old farts.
FORBES: VOIP Tipping Point
One of several problems that delayed the formation of the new government was the rear guard action waged by the Shiite Fadila Party to hang onto the Oil Ministry, which it controlled under former Prime Minister Ibrahim al-Jafari.
NPR: Iraq Oil Minister Vows to Fight Corruption, Smuggling
What about the rear guard?
FORBES: VOIP Tipping Point

In a battle, the rearguard is a group of soldiers who protect the back part of an army, especially when the army is leaving the battle.
If someone is fighting a rearguard action or mounting a rearguard action, they are trying very hard to prevent something from happening, even though it is probably too late for them to succeed.