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

But ordinary Americans are still frustrated by more costly gasoline and other prices. —Paul Wiseman, Los Angeles Times, 13 June 2026

And this isn’t just a problem for homeowners – costly insurance also affects renters and affordable housing providers, as landlords pass on costs to tenants, defer maintenance, postpone new building or face financial distress. —The Conversation, Fortune, 12 June 2026

Taking the time to understand the details now can help prevent costly surprises if your central air conditioning system needs repairs or replacement later. —Angelica Leicht, CBS News, 12 June 2026

In Game 2, a costly turnover and poor shot selection on consecutive possessions helped seal the Spurs' fate. —Bobby Burack Outkick, FOXNews.com, 12 June 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