KO or k.o.

1. Kick-off
2. Knockout
3. Knock out

To knock out

A knockout

• backstairs
• backstall
• backstalls
• backstarting
• backstays
• backstitch
• backstitches
• backstop
• backstops
• back story
• back straight
• back straights
• backstreet
• backstreet abortion
• backstreet abortions
• backstreets
• back stretch
• back stretches
• backstroke
• backstrokes
• backswimmer
• backswimmers
• backswing
• backswings
• backsword