noun
recoilless rifle
A military term for a lightweight artillery piece that vents propellant gases to the rear to eliminate recoil.
無反動銃は、発射時の反動を排気で相殺する火器である。
A recoilless rifle is a firearm that cancels out recoil at the moment of firing by venting exhaust gases.
Compound of 無 (mu, 'without') + 反動 (handō, 'recoil') + 銃 (jū, 'gun'). A calque of English 'recoilless rifle'.