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

Chief Justice John Roberts gave the Federal Communications Commission a temporary win on Thursday in its legal battle over who is entitled to favorable advertising rates in the closing weeks of the costly and hotly contested midterm elections. — Jack Birle, The Washington Examiner, 9 Oct. 2026

The larger spread also strengthens hospitals’ incentive to choose costlier drugs and move treatment into 340B billing sites. — Casey B. Mulligan, STAT, 8 Oct. 2026

The problem is that making even simple repairs is slow, costly, or impossible. — Jeffrey Ginsburg, New York Daily News, 8 Oct. 2026

Dyeing my whole head of hair seemed far too dramatic and costly. — Ellie Davis, Vogue, 8 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