"K" for "Kicking."
"K" for "Kick Ball."
Swim kicking is an example of plenty of kicking that happens in a lot of sports. In a running race, the "kick" is the final burst of speed as the finish line nears. Professional runners and those that want to win races need to have an exceptional kick, and that comes with lots of fitness and knowing yourself and your limits, then going beyond them.
"K" for "Karaoke"
In karaoke, getting kicked off the stage isn't a good thing.