1.
In a battle, the ~ is a group of soldiers who protect the back part of an army, especially when the army is leaving the battle.
N-SING: the N
2.
If someone is fighting a ~ action or mounting a ~ action, they are trying very hard to prevent something from happening, even though it is probably too late for them to succeed. (JOURNALISM)
Mr Urban looks increasingly like someone fighting a ~ action to keep their job.
PHRASE: V inflects