一刀[ittou] sword
一刀彫り[ittoubori] one-knife carving
一刀両断[ittouryoudan] cutting in two with a single stroke
印刀[intou] seal-engraving knife
円刃刀[enjintou] round-edged scalpel

快刀[kaitou] (literary) sharp sword
快刀乱麻[kaitouranma] solving a problem swiftly and skillfully
懐刀[futokorogatana] confidant
儀刀[gitou] ceremonial sword
軍刀[guntou] saber

隠忍[innin] patience
押っ忍[osu] greeting used between close male friends
勘忍[kannin] pardon
堪忍袋の緒が切れる[kanninbukuronoogakireru] to be out of patience
堅忍[kennin] perseverance

堅忍不抜[kenninfubatsu] indomitable perseverance
残忍[zannin] cruelty
恥を忍ぶ[hajiwoshinobu] to abide one's shame
忍ばせる[shinobaseru] to conceal
忍び[shinobi] stealth