Imagine an opponent rushing head on at you with all of their might... At the final moment, rather than defending yourself, you take at swipe at him/her too. This is the usual example for what is referred to as a counterattack.

99% of the time it's a mistake, but it's almost always a very tempting mistake to make, especially as a beginner learning right of way.

What WickerNipple describes is actually a simple counterattack, or a stop thrust (which, of course, is normally a very bad thing to do). The full range of counterattacks in fencing is much more broad, and some of them are actually quite useful. The only definition that ties them all together is that it is an attack against priority (right-of-way).

Some counterattacks:

• Stop Thrust
• Remise/Redoublement
• Imbroccata
• Opposition thrust
• Inquartata
• Passata Sotto