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

Make the most of this windfall of cash by putting it toward your costly credit card debt. —Jasmin Suknanan, CNBC, 15 Dec. 2025

Nigeria, the continent’s top crude oil producer, has for years relied on costly fuel imports due to its lack of refining capacity. —Alexander Onukwue, semafor.com, 15 Dec. 2025

If rates fall later, carrying a variable rate may be less costly. —Ryan Flanigan, CBS News, 15 Dec. 2025

This structure aims to provide developers with access to sophisticated testing infrastructure that would be too costly for any single organization to develop independently. —Aman Tripathi, Interesting Engineering, 14 Dec. 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