A knife (ナイフ Naifu) is a type of blade weapon.
It is generally small, although its most distinguishing characteristic is that it has one sharp edge.
Launch uses knifes when cooking, even chasing Krillin with a butcher's knife on Training Island after she turned into her evil form when he asked a brewsky for Master Roshi. Launch then sneezes again and, in doing so, she throws the knife in the air and it lands right in front of a frightened Krillin. Bulma, Oolong, and Chi-Chi also uses knifes when cooking, and many of the other Dragon Team member use them when eating.
Commander Red briefly threw a knife at Colonel Silver, or rather, a statue just a few inches behind him, upon briefing him as to the locations of the dragon balls in the anime only. During Goku's assault on Muscle Tower, Goku confronts a knife wielding soldier named Karot (カロット Karotto) after breaking into Muscle Tower. However like the rest of the soldiers, Karot is defeated by Goku (whom unbeknownst to either them had Saiyan birth name similar to the Earthling Karot's Kakarot).
General Blue uses a small knife to threaten Arale Norimaki when holding her hostage and demand that Goku surrender during their encounter at Penguin Village. Arale's creator Senbei Norimaki attempts to warn Blue that using a knife to threaten Arale is a very bad idea, which Arale soon confirms by licking the blade.
After his conversion into a Cyborg, Mercenary Tao has his left arm conceal a blade, which he uses to slice Tien Shinhan in the chest in their match in the 23rd World Martial Arts Tournament, such an action leading to his being disqualified from the tournament due to weapons usage being banned in the tournament, although Tao, having already been committed to killing Tien Shinhan regardless of the rules, did not care.
In King Kai's story about the Saiyan-Tuffle war a female Saiyan can be seen nonchalantly holding a dagger in her mouth by the blade. Gine also used knives and meat cleavers as a meat processing employee after retiring from the Saiyan Army.
In Dragon Ball Z: Broly - The Legendary Super Saiyan, during Paragus's flashback to how King Vegeta nearly had both himself and his son Broly executed, it was shown that the latter was stabbed with a dagger by a Saiyan guard, which nearly killed him.
In Dragon Ball Super: Broly, during the Occupation of Planet Vegeta Gine utilizes a meat cleaver in her job as a meat processing employee and she died holding her meat cleaver during the Genocide of the Saiyans after Bardock was overpowered by Frieza's Supernova.
In Dragon Ball GT: A Hero's Legacy, Mamba wields a large oversized kitchen knife which she attempts to use to kill and crave up Goku Jr. and Puck with while they are sleeping though Puck had deduced there was something suspicious about her human guise and she ended up only stabbing the bed before leaving the room to pursue them. She is later seen wielding the knife when she corners them in the kitchen where she cooks her human prey.
Video Game Appearance
In Dragon Ball Xenoverse 2, the Camo Bikini features a holster with a sheathed combat knife on the wearers left leg. However like other weaponry worn as part of certain clothing options it is purely cosmetic.
In Dragon Ball Z: Dokkan Battle, the Curiosity and Adventure Bulma (Youth) card features Bulma wearing her Camo Bikini (complete with the holster with her sheathed combat knife) from the manga cover for "Bulma's Big Mistake!!". However she doesn't utilize it in combat. Additionally Dogged Pursuit General Blue card depicts General Blue wielding his knife.