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 of costly

• 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

The change has proved costly because Venezuela lost one of its few remaining sources of legitimate income. —Stefano Pozzebon, CNN Money, 11 Nov. 2025

However, this strength makes both the production and disposal of the blades costly and energy-intensive. —Mrigakshi Dixit, Interesting Engineering, 10 Nov. 2025

Aside from an 11-yard scramble, the drive was a mess, with Wilson turtling up in the pocket and a costly drop from Wan’Dale Robinson. —Dan Duggan, New York Times, 10 Nov. 2025

Edison recently launched a compensation program for those impacted but costly litigation likely lies ahead. —Brian Sullivan, CNBC, 10 Nov. 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