# jack up

Source: https://englishreference.com/word/jack-up
Updated: 2026-08-27

## Senses

### 1. to lift with a tool

phrasal verb · CEFR B1

to lift something heavy, like a car, using a special tool called a jack.

For teachers: to raise or hoist an object, typically a vehicle, using a mechanical jack.

- We had to jack up the car to change the flat tire.
- The mechanic had to jack up the rear of the truck to inspect the damaged axle before providing a repair estimate.

Usage: Separable; the object can go between 'jack' and 'up'.

### 2. to increase prices

phrasal verb · CEFR B2 · Informal

to suddenly increase a price, fee, or amount by a lot.

For teachers: to increase a price, rate, or quantity, often in a sharp or opportunistic manner.

- The landlord decided to jack up the rent by twenty percent this year.
- Retailers often jack up their prices just before a major holiday, only to offer seemingly deep discounts during the actual sale.

Usage: Transitive; usually takes a direct object like 'prices', 'rates', or 'rent'.

### 3. to damage or ruin

phrasal verb · CEFR B2 · Informal · American English

to hurt someone or break something badly.

For teachers: to injure, damage, or ruin something; frequently used as a milder alternative to more vulgar terms.

- He really jacked up his knee playing football last weekend.
- The software update completely jacked up my computer's settings, and now I can't access my files.

Teaching tip: Common in American English as a way to describe physical injury or technical malfunction without using profanity.

### 4. to inject drugs

phrasal verb · CEFR C1 · Slang · Vulgar

to inject illegal drugs into a vein.

For teachers: to inject a drug intravenously.

- The movie showed the harsh reality of people who jack up in abandoned buildings.
- The documentary explored the lives of addicts who jack up daily, highlighting the lack of clean needle programs in the city.

## Examples

- The landlord decided to jack up the rent by twenty percent.
- Gas stations often jack up their prices right before a long holiday weekend when they know people need to travel.
- Speculators were accused of trying to jack up the value of the stock through aggressive and misleading marketing campaigns.

## Usage notes

- Teaching tip: contrast with 'raise' or 'increase' to show how 'jack up' implies a sudden, steep, or unwelcome change; it can also literally mean to lift a car with a tool.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.