Kangaroo court
Unauthorized court / unofficial court.
Keep at bay
Keep a safe distance.
Keep a low profile
Maintain self-privacy.
Keep in touch
Continue to be in contact
Keep mum
Keep quiet.
Keep one's ear to the ground
Focus on something to find out what is going on.
Keep one's feet to the ground
Be realistic. Accept the current situation.
Keep posted
Keep updated
Keep the finger cross
Hope bad things will not happen
Keep the chin up
Be brave / don't be discourage
Keep the shirt on
Calm down
Keep it for a rainy day
Keep something for the future when it might be needed
Keep the ball rolling
Continue doing something
Kick body and soul together
Work just enough to stay alive.
Kick away someone's the ladder
Eliminate someone's support
Kick the bucket
Die
Kick up someone's heel
Celebrate with someone
Keep your eye on the ball
Keep focus on something
Keep your nose clean
Stay away from any trouble
Kick the der
Take out something that support them
Kill to birds with one stone
Do two things at the same time.