Glossary
Wide swing
In one line: Coming out of cover with a wide, fast step, so you appear where the enemy's crosshair is not.
What it means
Someone holding an angle usually keeps their crosshair on the edge of the cover, where they expect you. With a wide swing you step out sideways with a big, fast movement: you appear further out than the edge, and the enemy has to move their crosshair to find you. That movement costs them time.
It works well against tight angles and against Operators; it works badly when there are several enemies, because you step into open space where other angles can see you.
An example
A defender is holding the edge of a doorway. Instead of leaning out slowly, you take a wide, fast step towards the middle of the passage: you appear far from their crosshair, stop and shoot first.