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 cost of diesel fuel has risen since last season, making every boat trip costlier. — Miami Herald, 15 Oct. 2026

Tens of thousands of drones have been launched in the wars in Gaza, Iran, and Ukraine, and countering them is costly, imprecise, and dangerous, with defensive missiles leading to all manner of falling debris. — Jeffrey Kluger, Time, 15 Oct. 2026

Leribault appeared to suggest that any plan to alter the Louvre would be costly and difficult in his Le Figaro interview published on Wednesday. — Alex Greenberger For Artnews, Robb Report, 15 Oct. 2026

What sets SpaceX apart is its ability to launch and maintain its own satellite network using reusable rockets, an advantage that's costly and difficult for competitors to replicate. — Kevin Simpson, CNBC, 14 Oct. 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