noun
A small explosive device thrown by hand or launched. The kanji 擲 means 'throw' or 'hurl', and 弾 means 'bullet' or 'projectile'.
兵士は擲弾を敵陣に投げ込んだ。
The soldier threw a grenade into the enemy position.
手榴弾 is the more common word for 'hand grenade'. 擲弾 is a less frequent synonym, often used in military contexts.
Compound of 擲 (throw, hurl) and 弾 (bullet, projectile). The reading is on'yomi. The word is a relatively modern coinage for 'grenade'.