# costly

/ˈkɑstɫi/ (US) · /kˈɒstli/ (UK)

Source: https://englishreference.com/word/costly
Updated: 2026-08-08

## Senses

### 1. expensive

adjective · CEFR B2

costing a lot of money.

For teachers: of high cost; expensive. Often used to imply that the price is higher than expected or justified.

- Buying a new car can be very costly when you include insurance.
- The renovation proved more costly than the initial estimates suggested, forcing the family to dip into their long-term savings.

### 2. causing loss or damage

adjective · CEFR C1 · Formal

causing a lot of problems, damage, or the loss of something important.

For teachers: resulting in great loss, damage, or sacrifice; having negative consequences that are difficult to recover from.

- A costly mistake at work resulted in the company losing a big client.
- The general's decision to delay the retreat proved to be a costly error that resulted in heavy casualties.

## Examples

- The repairs to the old car were very costly.
- A costly mistake in the final minutes of the game led to the team's defeat.
- The project was eventually abandoned after a series of costly delays made the original budget impossible to maintain.

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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.