debole
The flexible part of the blade near the tip of light swords such as rapiers.
There are two parts to the sword: the forte and the debole. The forte begins from the hilt, extending as far as the middle of the blade; and the remainder is called the debole. The forte is for parrying, and the debole for striking. This is really important because: if you always keep your forte in the way of the opponent's debole, you will never be hit.
Where it comes from
From Italian debole, meaning "weak", equivalent to the French foible.
Adapted from the Wiktionary entry debole (CC BY-SA 4.0).