Definition from Wiktionary, the free dictionary
rearguard (plural rearguards)
- (military) The rearmost part of a force, especially a detachment of troops that protect the rear of a retreating force.
- (soccer) The defence, collectively the defenders.
2011 January 22, Phil McNulty, “Aston Villa 1 - 0 Man City”, BBC:
- Mancini's side only showed enough ambition when it was too late and by then battle lines were drawn as James Collins and former City captain Richard Dunne fought a magnificent rearguard action at the heart of Villa's defence.
- Usually used attributively.