costly

adjective

cost·​ly ˈkȯs(t)-lē 

costlier; costliest

1

a

: commanding a high price especially because of intrinsic worth

costly gems

b

: rich, splendid

2

: made or done at heavy expense or sacrifice

a costly mistake

costliness noun

Synonyms

• expensive
• valuable

Examples of costly in a Sentence

We use less costly materials in our products.

It was too costly to fix her car after the accident, so she decided to buy a new car instead.

They won the game, but their best player was injured, so it was a costly victory.

The decision to wait could be a costly mistake.

Recent Examples on the Web

Opting into a federal voucher program that is costly and ineffective would be irresponsible for our state and our students. —Chicago Tribune, 23 July 2025

Georgia farmers are facing a costly and growing threat from an unexpected source − wild pigs. —Vanessa Countryman, USA Today, 22 July 2025

The humanitarian community has long wrestled over airdrops, which are costly and difficult to execute. —Chris Boccia, ABC News, 22 July 2025

The Hidden Cost Of Executive Self-Protection In boardrooms and strategy sessions globally, talented executives are making the same costly mistake: optimizing for personal safety instead of business outcomes. —John Kania, Forbes.com, 22 July 2025

Word History

First Known Use

14th century, in the meaning defined at sense 1a

Kids Definition

costly

adjective

cost·​ly ˈkȯs(t)-lē 

costlier; costliest

1

: of great cost or value

costly furs

2

: gained at great expense or sacrifice

a costly victory

costliness noun