Combat knife

Combat knife is a weapon in Deus ex, and Deus Ex: Invisible War and is oftenly considered the worst weapon in the game, due to the fact of it's low damage, and it being a "Low Tech" weapon that doesn't knock out NSF makes it a waste of inventory.

In-game Description
Deus Ex Description "A ultra-high carbon steel knife."

Deus Ex: Invisible War Description "A heavy military knife. Ultra high carbon steel. Virtually unbreakable. Heft and balance make it suitable for slashing and stabbing."

Unique weapons
In Deus Ex 2, There is a unique variant of a standard combat knife: the Toxin Blade.

"Prototype special forces combat knife. Microporous metal releases toxins on contact. Designed for political assassination"