Rereward

(Josh. 6:9), the troops in the rear of an army on the march, the rear-guard. This word is a corruption of the French arriere-garde. During the wilderness march the tribe of Dan formed the rear-guard (Num. 10:25; comp. 1 Sam. 29:2; Isa. 52:12; 58:8).

Part of speech: noun (n.)

The rear quard of an army. [Obs.]