| knock someone into the middle of next week | | | |
| knock someone's socks off | | | |
| knock together | | | |
| know inside and out | | | |
| know one's shit | | | |
| know someone from Adam | | | |
| know the score | | | |
| know which side one's bread is buttered on | | | |
| knuckle under | | | |
| kao peh kao bu | | | |
| keep a civil tongue in one's head | | | |
| keep a cool head | | | |
| keep a low profile | | | |
| keep an eye open | | | |
| keep an eye peeled | | | |
| keep company | | | |
| keep house | | | |
| keep it in the family | | | |
| keep it one hundred | | | |
| keep it together | | | |
| keep off the streets | | | |
| keep on about | | | |
| keep one's chin up | | | |
| keep one's ears open | | | |
| keep one's eyes peeled | | | |
| keep one's hair on | | | |
| keep one's head above water | | | |
| keep one's head on a swivel | | | |
| keep one's lips sealed | | | |
| keep one's nose clean | | | |
| keep one's pants on | | | |
| keep one's stick on the ice | | | |
| keep one's tits on | | | |
| keep on truckin' | | | |
| keep quiet | | | |
| keep someone amused | | | |
| keep someone company | | | |
| keep someone on ice | | | |
| keep someone posted | | | |
| keep straight | | | |
| keep the ball rolling | | | |
| keep the home fires burning | | | |
| keep the pot boiling | | | |
| keep the wolf from the door | | | |
| keep up appearances | | | |
| keep up with the times | | | |
| kernel of truth | | | |
| keys to the kingdom | | | |
| kick against the pricks | | | |
| kick ass and take names | | | |
| kick at the can | | | |
| kick bollocks scramble | | | |
| kick in | | | |
| kicking boots | | | |
| kick into the long grass | | | |
| kick it | | | |
| kick off | | | |
| kick out | | | |
| kick rocks | | | |
| kick someone's ass | | | |
| kick some tail | | | |
| kick the beam | | | |
| kick the can down the road | | | |
| kick the tires | | | |
| kick to the curb | | | |
| kick up one's heels | | | |
| kick with the other foot | | | |
| kiddie table | | | |
| killer instinct | | | |
| kill me | | | |
| kill the fatted calf | | | |
| kill trees | | | |
| kindest regards | | | |
| kindle-fire | | | |
| kindred soul | | | |
| kind regards | | | |
| king of beasts | | | |
| king of the castle | | | |
| King of the Jungle | | | |
| King Shit of Turd Island | | | |
| kiss and cry | | | |
| kiss and tell | | | |
| kiss arse | | | |
| kiss my ass | | | |
| kiss off | | | |
| kiss someone's ass | | | |
| kiss the gunner's daughter | | | |
| kiss up to | | | |
| knee-deep in the Big Muddy | | | |
| knee-jerk reaction | | | |
| knight in shining armor | | | |
| knit one's brows | | | |
| knit together | | | |
| knock a dog off a gut wagon | | | |
| knock down | | | |
| knock for a loop | | | |
| knock it off | | | |
| knock oneself out | | | |
| knock on wood | | | |
| knock out of the box | | | |