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

Employees working 70 hours often produce no more than those working 55, making extreme schedules both costly and counterproductive. —Caroline Castrillon, Forbes.com, 15 Sep. 2025

Broncos quarterback Bo Nix, who went 22-of-30 for 206 yards and three touchdowns, also threw a costly interception in Colts territory early in the fourth quarter, taking points off the board. —Scott Thompson, FOXNews.com, 15 Sep. 2025

By replacing outdated infrastructure with real-time oversight, the company gives clients a scalable way to modernize security without a costly hardware overhaul. —Sixteen Ramos, USA Today, 15 Sep. 2025

Learning a new one is an option, but that's a time-consuming and potentially costly solution. —Gabriel Zamora, PC Magazine, 15 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