The Knife, (or its reskin, the Scalpel), is a common sharp weapon that has the unique attribute of being near silent.
The Knife has a melee range of three studs, swings every 0.4 seconds, and deals 20 damage. The Scalpel has the same stats but swings every 0.35 seconds.
Time to kill/down is ~2.0 seconds. (Note: The Knife/Scalpel, along with the Umbrella, are the only weapons that cannot break down doors.)