(military) The rear rank of a body of troops when faced about and standing in that position.

Alternative form of pain in the ass

(military) That part of an army that is not needed to directly combat the enemy. / (military, by extension) The administrative and supply departments of an army.

simple past tense and past participle of rear up

Third-person singular simple present indicative form of rear up

present participle of rear up

To rise up, especially an animal like a horse rising up on its rear legs.

(informal) A minor automobile accident in which contact is made between the front of one vehicle and the rear of another.

(of a quadruped, usually a horse) To stand on two rear legs, as an aggressive or fearful gesture.

Synonym of back projection