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

Yet, while lithium is abundant on our planet, mining clean sources of it can be difficult, costly, and environmentally damaging. —New Atlas, 30 Nov. 2025

Best Wayfair Black Friday Area Rug Deals An area rug is a quick and easy way to refresh a room without redoing your decor or investing in potentially costly furniture. —Jacqueline Tempera, PEOPLE, 30 Nov. 2025

Installation is also costly unless your home already has the proper setup. —Angie Hicks, Boston Herald, 30 Nov. 2025

Hurts completed just over half of his passes and had two costly turnovers in the second half, including losing a fumble on a tush push. —Ryan Morik, FOXNews.com, 29 Nov. 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