costly

/ˈkɔːstli/

Say it: KAWST-lee

1. adjective Costing a lot of money; expensive.
The renovations were beautiful but far too costly for our budget.
2. adjective Involving great loss, sacrifice, or suffering.
It was a costly victory, as the company lost its best engineers in the process.
3. adjective Rich, sumptuous, or of great value.
The museum displayed the king's costly robes, woven with gold thread.

📖 Seen in the wild

The delay in production proved to be a costly mistake for the company.
collected by @vocablast

✏️ costly in a sentence

Delaying the decision proved to be a costly mistake for the campaign.
They opted for a less costly alternative to the name-brand medication.
The legal battle was a long and costly affair for both sides.
Maintaining such a large, historic home is a costly undertaking.
His pride was a costly flaw that ultimately led to his downfall.
The company's failure to adapt to new technology was a costly error in judgment.

🔁 Synonyms & antonyms

expensive pricey exorbitant dear steep high-priced valuable precious

expensive · focuses purely on high monetary price, whereas 'costly' can also imply a negative consequence.

pricey · a more informal equivalent of 'expensive'.

exorbitant · implies the price is unreasonable or excessive, which 'costly' does not always suggest.

dear · a somewhat formal or old-fashioned term, more common in British English.

Opposites: cheap, inexpensive, affordable, economical

🌱 Where it comes from

The word 'costly' simply combines the noun 'cost' with the adjective-forming suffix '-ly'. 'Cost' itself traces back through Old French to the Latin verb 'constare', meaning 'to stand at' or 'to stand firm', which was also used to mean 'to cost'. So, something 'costly' is literally something that 'stands at' a high price.

🧩 How it's used

Common patterns:

costly mistakecostly errorcostly delayprove costlycostly victory

'Costly' and 'expensive' are often interchangeable when talking about money, but 'costly' has a broader range. It frequently carries a negative connotation, implying that the high price led to a bad outcome or required a great sacrifice. This is why we speak of a 'costly mistake' or a 'costly error', where the 'cost' isn't money but rather damage, loss, or regret. 'Expensive' is more neutral and sticks to financial price.

Word family: cost, costliness

💬 Quick answers

What does 'costly' mean?

Costly means that something has a high price, either in money or in terms of loss, sacrifice, or other negative consequences.

What is the difference between 'costly' and 'expensive'?

'Expensive' almost always refers to a high monetary price. 'Costly' can also mean high-priced, but it often carries an added sense of negative outcome or sacrifice, as in a 'costly mistake'.

Is 'costly' a formal word?

'Costly' is a neutral word that is appropriate for both formal and informal situations, from academic papers to everyday conversation.

1 word nerd collected it V

Want "costly" to actually stick?

Save it to your own vault, let AI explain it, practice till it's yours.

Start for free →