noun
shuriken; throwing star; small throwing blade
A traditional Japanese concealed weapon, often star-shaped or spike-shaped, used by ninja.
忍者は手裏剣を投げて敵を倒した。
The ninja threw a shuriken and defeated the enemy.
博物館で本物の手裏剣を見た。
I saw a real shuriken at the museum.
A broader term for hidden weapons; 手裏剣 is a specific type of 暗器.
From 手裏 (shuri, 'in the hand') + 剣 (ken, 'blade'). The exact historical derivation is uncertain, but the term refers to a blade concealed in the hand.