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

That report recommended keeping the SAT and ACT in place until UC could develop its own admissions test, an idea UC later concluded was too difficult and costly. — Jaweed Kaleem, Los Angeles Times, 17 Sep. 2026

There was one play against Missouri when pressure closed in and Marshall tried to avoid a costly sack. — Taylor Eldridge, Kansas City Star, 17 Sep. 2026

An early withdrawal penalty on CDs should always be avoided, but one levied against a $50,000 5-year CD, in particular, could be especially costly. — Matt Richardson, CBS News, 17 Sep. 2026

Creating the pipeline Although skilled chip workers are concentrated overseas, bringing over foreign talent on H-1B visas has become a costly and cumbersome process. — Katie Tarasov, CNBC, 17 Sep. 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