Keep An Eye On Him: to watch carefully or to keep someone out of trouble
Example: Keep an eye on my children your brother while I’m out, please.
Keep Body and Soul Together: to be able to pay for your food, clothing and somewhere to live.
Example: If you earn enough to cover your basic expenses, but nothing more than that, you earn enough to keep body and soul together.
Keep Your Chin Up: say to someone in a difficult situation in order to encourage them to be brave and try
Example: Keep your chin up! We will win this job.
Keeping her chin up: happy despite bad things
Example: She seems to be keeping her chin up.
Kick the bucket: Die, Pass away
Example: When I kick the bucket, you can just bury me under a tree.
Kill Two Birds with One Stone: to accomplish two different things at the same time
Example: Walking to work kills two birds with one stone. It saves money and gives your health life.
Kitty-Corner (Catty-Corner): used to describe two things that are located across from each other on opposite corners, diagonally opposite
Example: My boss house was kitty-corner from mine.
Knee Jerk Reaction: a quick and automatic reaction without considering carefully
Example: Their response was 'NO' without considering, even thinking; it was a knee-jerk reaction.
Knock On Wood: to wish for good luck
Example: This deal will make you and a contractor happy. Knock on wood!
Know the Ropes: to have a knowledge or experience how to do
Example: Anybody who has been doing or seeing the job for a few days should know the ropes.