costly

The word “costly” means expensive, or requiring a heavy price to be paid. In plain terms, expensive in money, or damaging in some other serious way, like a "costly error.".

“Costly” is pronounced KOST-lee (/ˈkɒst.li/ in IPA).

Here is “costly” used in a sentence: “Repairing the roof turned out to be a costly job.”

The opposite of “costly” — its antonyms — is costlessly.

“Costly” is an adjective.

The word “costly” comes from Middle English. From Middle English costly, formed from cost plus -ly.

“Costly” is a fairly common word in modern English, usually learned at around the B2 level.

Both mean requiring a lot of money and often overlap. However, "costly" frequently implies a heavy price beyond money — such as damage or loss, as in "a costly mistake" — while "expensive" refers more directly to a high monetary price.

Costly and pricey both describe something that costs a lot, but pricey is more informal and casual. Costly is more formal and can also suggest serious consequences, not just a high price tag.

Yes. Besides meaning expensive, costly can describe anything that requires a heavy price to be paid, such as a costly error in judgement or a costly victory won at great loss.

Costly means something has a high price or requires a heavy cost to obtain. Valuable means something is worth a great deal, whether in money, usefulness, or importance. A costly item is not always valuable, and a valuable item is not always costly.