costly

[kawst-lee, kost-]

adjective

costlier, costliest 

1. costing much; expensive; high in price.

   a costly emerald bracelet; costly medical care.

   Synonyms: high-priced, dear

2. resulting in great expense.

   The upkeep of such a large house is costly.

3. resulting in great detriment.

   It was a costly mistake because no one ever trusted him again.

4. of great value; very valuable; sumptuous.

5. lavish; extravagant.

costly

/ ˈkɒstlɪ /

adjective

1. of great price or value; expensive

2. entailing great loss or sacrifice

   a costly victory

3. splendid; lavish

Other Word Forms

• costliness noun
• overcostliness noun
• overcostly adjective
• uncostly adjective

Word History and Origins

Origin of costly¹

First recorded in 1350–1400, costly is from the Middle English word costli. See cost, -ly

Synonym Study

See expensive.

Example Sentences

The hard part, and the costly part, was building out the infrastructure needed to link distant cities and millions of homes and offices.

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The pumps require more electricity to operate in extremely cold climates, and could ultimately be more costly to buy and operate than natural-gas furnaces, says Davis.

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With their children grown, they may feel free to address what has long bothered them, like clutter and costly in-home care.

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Memphis is the front line of Musk’s costly foray into the AI wars.

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The new policy, which is set to go into effect Dec. 16, offers a glimpse of how tech companies plan to monetize costly artificial-intelligence efforts.

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Related Words

• catastrophic 
• disastrous 
• ruinous