noun
Military term for a soldier held in reserve or a newly enlisted recruit. Used in historical and modern military contexts.
戦時中、多くの補充兵が前線に送られた。
During the war, many reservists were sent to the front lines.
彼は補充兵として軍隊に入った。
He joined the army as a recruit.
Compound of 補充 (ほじゅう, 'replenishment, supplement') and 兵 (へい, 'soldier'). The term is straightforward and transparent in meaning.