Leela wields a knife

Leela defends herself and James Skinsale from the Rutan scout. (TV: Horror of Fang Rock)

A knife was a device used for cutting or stabbing. According to the Thirteenth Doctor, "only idiots carr[ied] knives." (TV: The Woman Who Fell to Earth)

A carnivorous flower caught the First Doctor on Tiro and almost digested him, but he escaped by hacking at the plant's insides with his knife. (PROSE: Terror on Tiro)

Leela used her knife to try to keep a Rutan scout away from her and James Skinsale in the Fang Rock lighthouse. (TV: Horror of Fang Rock)

The Fifth Doctor, stuck in the streets of Wallachia with Peri in 1462, was stabbed in the chest with a poisoned knife. (AUDIO: Son of the Dragon)

Shockeye killed Oscar Botcherby with a meat knife when he refused to accept the twenty narg note Shockeye offered as payment. (TV: The Two Doctors)

Major Raykal was murdered in Turkey by having his throat slashed open by an unknown killer with an non serrated knife. (PROSE: Eternity Weeps)

The Eighth Doctor tricked Elizabeth Kelly into stabbing him in the heart with a knife. This was so he could enter the realm of death and communicate with the spirit of Sebastian Chiltern. (PROSE: Camera Obscura)

When a chef on the Orient Express saw the Foretold, he grabbed a knife and waved it around to deter the mummy. (TV: Mummy on the Orient Express)

The Life Knife was a three-bladed knife that was associated with the resurrection gauntlet. Those killed with the knife were easier for the gauntlet to resurrect. (TV: Everything Changes, They Keep Killing Suzie)

A Gallifreyan Army knife was issued to the Chancellery Guard. The Doctor had one which was marked as property of Castellan Spandrell. (PROSE: Blood Harvest)

Leela once killed a Sontaran by expertly throwing a knife into the probic vent on the back of the Sontaran's neck. (TV: The Invasion of Time)