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

Officials said achieving Connecticut’s ambitious goals are important for curbing the costly impacts of climate change. — Stephen Underwood, Hartford Courant, 13 Nov. 2026

Orlando Sentinel Community News Fund Gathering public records and sharing news shouldn’t be costly. — Scott Maxwell, The Orlando Sentinel, 13 Nov. 2026

This October marks the one-year anniversary of Hurricane Melissa, the strongest and costliest hurricane to ever hit Jamaica. — Megan Spurrell, Condé Nast Traveler, 13 Nov. 2026

Because ongoing emergency veterinary treatment is costly, rescuers are asking the public for support. — Joan Murray, CBS News, 13 Nov. 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