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 former junkyard is seen as ripe for future redevelopment, but an environmental clean-up is clearly a costly hurdle to be cleared. —Kenneth R. Gosselin, Hartford Courant, 17 May 2026

Youth experience greater emotional stability, families become more resilient, and communities reduce reliance on costly emergency interventions and out-of-home placements. —Maria Bledsoe, The Orlando Sentinel, 17 May 2026

Any disruption to the strait would force vessels on costly dayslong detours. —Mithil Aggarwal, NBC news, 16 May 2026

Other companies saw design as a costly distraction amid an even costlier push to adopt AI. —Nicholas Gordon, Fortune, 16 May 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