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 permits are costly as well and would-be living seawall builders need a lot of them — from the city, the state, the county and the federal government. — Alex Harris, Miami Herald, 22 July 2026

At the same time, Rudolph was given a chance to win an important late-season game for the Steelers last year and committed a pair of costly turnovers in a loss to Chicago. — Mike Defabo, New York Times, 21 July 2026

This shift can’t be blamed entirely on America’s costly labor and strict regulations. — James Surowiecki, The Atlantic, 21 July 2026

That criticism echoed complaints from soldiers and veterans over heavy casualties in costly front-line assaults. — ABC News, 21 July 2026

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