Lock sb in Meaning, Examples & How to Use the Phrasal Verb

What Does “Lock sb in” Mean?

“Lock sb in” means to keep someone inside a room or building by locking the door, preventing them from leaving.

Introduction

The phrase “lock sb in” is a common phrasal verb in English used to describe the action of keeping someone confined within a space by locking doors or barriers. Understanding the “lock sb in meaning” helps learners grasp situations where physical restriction is involved. It is often used in both literal and figurative contexts, such as locking someone inside a room or figuratively committing someone to a decision or contract. This phrase is useful in daily conversations, storytelling, and writing, giving speakers a clear way to express control or restriction.

Quick Info Box

• Phrasal verb: lock somebody in
• Type: transitive
• Level: B1
• Short meaning: to keep someone inside by locking a door or barrier

Structure (Grammar Rules)

The phrasal verb “lock sb in” is separable because the object (sb = somebody) comes between the verb and the particle “in.” The structure is:

• lock + somebody + in

Example: “They locked him in the room.”

You cannot say “lock in somebody” in this context; it’s incorrect.

How to Use “Lock sb in”?

Use “lock sb in” when you want to describe the act of physically locking a person inside a place. This can be used literally, such as locking a child in a room to keep them safe, or figuratively, such as locking someone in a contract or agreement (though this latter use is less common and usually phrased differently).

It is often followed by the place or object where the person is locked in, for example, “lock someone in a cage” or “lock someone in an office.”

Examples

Imagine you are telling a story about a security guard who accidentally locked a visitor inside a building.

• They locked the visitor in the building by mistake.
• She locked her brother in the basement as a prank.
• The teacher locked the students in the classroom during the storm to keep them safe.
• He was locked in the office until the manager arrived.
• Don’t lock me in the house all day!

These examples show “lock sb in in a sentence” used in everyday situations.

Common Mistakes

People often confuse the order of words or use the wrong preposition when using this phrase.

• Incorrect: They locked in him the room.
• Correct: They locked him in the room.
• Incorrect: She locked in the kids.
• Correct: She locked the kids in.

Remember the object must come between “lock” and “in.”

Differences / Synonyms

“Lock sb in” is similar to “trap sb in” or “confine sb,” but there are differences. “Trap sb in” usually implies danger or being stuck unexpectedly, while “lock sb in” emphasizes the physical action of locking.

For example, “lock sb in” focuses on the door or lock, but “trap sb in” might mean being stuck in a difficult situation without a way out.

Other synonyms include “shut sb in,” but “lock sb in” specifically involves locking.

Common Collocations

Using “lock sb in” with common objects helps learners use the phrase naturally.

• lock someone in a room – to keep someone inside a room
• lock someone in a cage – often used for animals or metaphorically
• lock someone in a building – keep someone inside a building
• lock someone in a cell – used for prisoners
• lock someone in the house – keep someone inside a house

Related Phrasal Verbs

Here are related phrasal verbs of lock sb in:

• Lock Sb Away
• Lock Sb Up
• Lock Sb Out
• Lock Sth Out
• Lock Sth In

Real-life Dialogue

Here’s a short conversation where two friends talk about an accident at school.

Anna: Did you hear what happened to Tom yesterday?

Ben: No, what?

Anna: The janitor accidentally locked him in the classroom after school.

Ben: Wow! How long was he locked in?

Anna: For almost an hour until someone found him.

Practice

Try to complete the sentences with the correct form of “lock sb in.”

• They __________ the children __________ the gym during the fire drill.
• Don’t __________ me __________ the house all day!
• The security guard __________ the visitors __________ the building by mistake.
• She __________ her little brother __________ the closet as a joke.

FAQs

• What does “lock sb in” mean? It means to keep someone inside a place by locking the door or barrier.
• Is “lock sb in” separable? Yes, the object goes between “lock” and “in.”
• Can I say “lock in sb”? No, the correct order is “lock sb in.”
• Is “lock sb in” used only literally? Mostly yes, but it can sometimes be used figuratively.
• What are common phrases with “lock sb in”? Lock someone in a room, cage, building, or house are common.