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

An example of this could be quality control, where a supply chain disruption can have massive (and costly) downstream effects. —Ed Jennings, Forbes.com, 11 July 2025

Without proper maintenance, homeowners could face more costly problems down the line. —Rachel Barber, USA Today, 11 July 2025

The organization is currently operating out of two storage units, which Hansford said is costly. —Lillian Metzmeier, The Courier-Journal, 10 July 2025

The University of California’s California Health Benefits Review Program last October already tallied 95 costly state health-insurance mandates. —The Editorial Board, Oc Register, 9 July 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