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Processed with VS1Recognize phrases for hoping for luck, giving casual permission, and responding to criticism.
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Source: VOA Learning English · Words and Their Stories
View original article & transcriptThis episode explores several unrelated meanings built around “knock.” People say “knock on wood” after mentioning good fortune, “don’t knock it till you’ve tried it” to discourage premature criticism, and “knock it off” to tell someone to stop. “Knock yourself out” can grant casual permission, while “knock ’em dead” is an informal way to wish a friend success.
Cultural note: “Knock on wood” is a superstition some people say playfully; it is not a guarantee of luck. “Knock it off” can sound sharp, and “knock yourself out” is very informal—both can be misunderstood if tone or permission is unclear.
Keep exploringThe verb “knock” can mean tapping, criticizing, stopping, or encouraging. The surrounding words—and the relationship between speakers—do the work.
Phrase guide · 5 expressions
Original explanations and examples, created for learners. Save a card for later or hear the phrase spoken by your browser.
Recognize a familiar expression said after mentioning good fortune.
Meaning
A phrase said after mentioning good fortune, to express hope that it continues.
Tone & use
Often said playfully or out of habit; it reflects superstition, not a factual way to control events.
Example
“I haven’t caught a cold all winter—knock on wood.”
Understand casual ways to invite someone to go ahead.
Meaning
Go ahead and do something; the speaker is giving permission or showing they do not object.
Tone & use
Very informal and context-dependent; it can sound dismissive. Make sure the permission is clear.
Example
“You can use the kitchen to make tea—knock yourself out.”
Respond to premature criticism or ask someone to stop.
Meaning
Do not criticize an experience or idea before you have tried or considered it.
Tone & use
Informal advice. It should not be used to pressure someone into an unsafe or unwanted activity.
Example
“I was unsure about the new recipe, but my friend said, “Don’t knock it till you’ve tried it.””
Meaning
Stop doing something irritating or inappropriate.
Tone & use
Direct and somewhat forceful. Use a calmer request such as “Could you stop, please?” in formal settings.
Example
“The classmates kept tapping their pencils, so the teacher asked them to knock it off and listen.”
Wish a friend success in a relaxed, informal way.
Meaning
Do extremely well and impress people.
Tone & use
Friendly, informal encouragement, often before a performance, interview, or presentation; not literal.
Example
“You’ve practiced your talk all week. Knock ’em dead at the conference!”
Knowledge check
Choose the expression that best fits each situation.
Try it · Choose the best expression
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