Explore popular idioms beginning with the letter 'K' and enhance your language skills while having fun.

American Idioms Starting with K

To force oneself not to laugh, even though one wants to. ex. "He was saying the stupidest things, and I was finding it hard to keep a straight face."

To uphold one's promise. ex. "He's a very honorable person who always keeps his word."

To not let others know about something. To not reveal something. ex. "Hey, don't tell anyone about your time in prison. Keep it to yourself."

A phrase said to cancel out (imaginary) bad luck.

To know something completely and thoroughly. ex. "Let me show you around - I know this neighborhood inside-out."

To know the facts. To know how things go.

To not allow someone to sleep. ex. "The neighbors' party kept me up all night."

To watch. To pay attention to. ex. "I have to go to the store. Can you please keep an eye on the baby for 10 minutes?"

To maintain a record of. ex. "I don't know where all my money goes. It's hard to keep track of my expenses."

A person who acts like they know everything. ex. "Robert is so conceited! Yeah, he's a real know-it-all."