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

• 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

Spending will continue to increase and the debt burden—already unbearable—will grow heavier and more costly. —Miranda Jeyaretnam, Time, 9 Sep. 2025

In response to this, some organizations go all-in on customization, but this can lead to system complexity and costly updates. —Shiv Kaushik, Forbes.com, 8 Sep. 2025

Many are cemented into the ground, making their relocation either structurally impossible or prohibitively costly. —Max Klaver, Miami Herald, 8 Sep. 2025

Land, materials and labor are costly. —Ben Jones, CNN Money, 8 Sep. 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