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

But shipping experts say the complex and costly measure wouldn’t restore normal traffic quickly. —Amena Bakr, semafor.com, 9 Mar. 2026

But this is a really costly thing for the country and the families that put their lives on the line and their spouses and their brothers and sisters. —Hannah Fry, Los Angeles Times, 9 Mar. 2026

An Ontario couple’s pandemic-era home renovation turned into a financial nightmare after ancestral Indigenous remains were discovered on their property, triggering a provincial law that forces homeowners to fund costly archaeological investigations with little hope of relief. —Ryan Brennan, Miami Herald, 9 Mar. 2026

Clinical visits, gasoline, transportation, and food, some as costly takeout meals purchased outside of regular grocery budgets, can adversely impact family finances. —Karie Angell Luc, Chicago Tribune, 9 Mar. 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