A rearguard is a part of a military force that protects it from attack from the rear, either during an advance or withdrawal. The term can also be used to describe forces protecting lines, such as communication lines, behind an army. Even more generally, a rearguard action may refer
idiom An idiom is a phrase In everyday speech, a phrase is any group of words, often carrying a special idiomatic meaning; in this sense it is synonymous with expression. In Linguistics#Analysis, linguistic analysis, a phrase is a group of words (or pos ...
atically to an attempt at preventing something though it is likely too late to be prevented; this idiomatic meaning may apply in either a military or non-military context.


The term rearguard (also ''rereward'', ''rearward'') originates from the medieval custom of dividing an army into three '' battles'' or ''wards'';
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, Main (or Middle) and Rear. The Rear Ward usually followed the other wards on the march and during a battle usually formed the rearmost of the three if deployed in
column A column or pillar in architecture and structural engineering is a structural element that transmits, through compression (physical), compression, the weight of the structure above to other structural elements below. In other words, a column is ...
or the left-hand ward if deployed in
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Original usage

The commonly accepted definition of a rearguard in military tactics was largely established in the battles of the late 19th century. Before the mechanization of troop formations, most rearguard tactics originally contemplated the use of
cavalry Cavalry (from the French word ''cavalerie'', itself derived from "cheval" meaning "horse") are soldiers or warriors who Horses in warfare, fight mounted on horseback. Cavalry were historically the most mobile of the combat arms, operating as li ...

forces. This definition was later extended to highly mobile infantry as well as mechanized or armored forces. Narrowly defined, a rearguard is a covering detachment that protects the retreating main ground force element (main body), or column, and is charged with executing defensive or retrograde movements between the main body and the enemy to prevent the latter from attacking or interfering with the movement of the main body.

Contemporary usage

A more expansive definition of the rearguard arose during the large-scale struggles between nation-states during the First and Second World Wars. In this respect, a rearguard is a minor unit of regular or irregular troops that protect the withdrawal of larger numbers of personnel (military or civilian) during a retreat, by blocking, defending, delaying, or interfering with advancing enemy forces in order to gain time for the remainder to regroup and reorganize. Rearguard actions may be undertaken in a number of ways, either in defense, such as by defending strongpoints or tactically important terrain, or by pre-emptively assaulting the enemy as he prepares his own offensive operations with a ''spoiling attack''. Two examples of rearguard actions are: *
Rorke's Drift The Battle of Rorke's Drift (1879), also known as the Defence of Rorke's Drift, was an engagement in the Anglo-Zulu War. The successful British defence of the mission (station), mission station of Rorke's Drift, under the command of Lieutenants ...
during the
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(1879)Crowley, Liz and Hand, David.
Football, Europe and the Press
', p. 31 (Routledge 2013).
Battle of Dunkirk The Battle of Dunkirk (french: Bataille de Dunkerque, link=no) was fought in Dunkirk (Dunkerque), France France (), officially the French Republic (french: link=no, République française), is a country primarily located in Western ...
(1940) Another contemporary example is the rearguard action fought by small units of the
Serbian Army The Serbian Army ( sr-cyr, Копнена војска Србије, Kopnena vojska Srbije, lit=Serbian Land Army) is the land-based component of the Serbian Armed Forces, responsible for defending the sovereignty and territorial integrity of Se ...
to protect retreating Serbian troops, the
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, and Serbian refugees from advancing forces of the
Central Powers The Central Powers, also known as the Central Empires,german: Mittelmächte; hu, Központi hatalmak; tr, İttifak Devletleri / ; bg, Централни сили, translit=Tsentralni sili was one of the two main coalitions that fought World W ...
during their retreat through Albania and Montenegro in 1915–1916. The nature of combat in rearguard actions involving combat between armies of nation-states is typically desperate and vicious, and rearguard troops may be called upon to incur heavy casualties or even to sacrifice all of their combat strength and personnel for the benefit of the withdrawing forces.

Idiomatic expression

Fighting or mounting a rearguard action is also sometimes an
idiom An idiom is a phrase In everyday speech, a phrase is any group of words, often carrying a special idiomatic meaning; in this sense it is synonymous with expression. In Linguistics#Analysis, linguistic analysis, a phrase is a group of words (or pos ...
atic expression, outside any military context. That idiom refers to trying very hard to prevent a thing from happening even though it is probably too late.
Cambridge Idioms Dictionary
' (2nd ed., Cambridge University Press, 2006) via ''
The Free Dictionary The Free Dictionary is an American online dictionary A dictionary is a listing of lexemes from the lexicon of one or more specific languages, often arranged Alphabetical order, alphabetically (or by radical-and-stroke sorting, radical an ...
An example of a famous rearguard action outside the military context is the effort by Roman emperor Julian around 362 A.D. to restore
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as the state religion instead of Christianity. Sportswriters employ the idiom as well.Reavis, Tracey.
The Life and Career of David Beckham: Football Legend, Cultural Icon
', p. 70 (Rowman & Littlefield, 2014).

See also

* Quick reaction force *
Vanguard (military tactics) The vanguard (also called the advance guard) is the leading part of an advancing military formation. It has a number of functions, including seeking out the enemy and securing ground in advance of the main force. History The vanguard derives ...
* Battle of Tirad Pass


{{Authority control Military tactics