High-priced, pricey, expensive.
Costly.
Dear,costly and high-priced are some of the synonyms for expensive.
Expensive. Dear. Pricey.
Synonyms: dear, expensive, pricy. Antonyms: cheap, inexpensive.
Another word for expensive is "costly." Other synonyms include "pricey" and "lavish," each conveying a sense of high cost or value.
The word "expensive" is similar in meaning to "costly." Both terms describe something that requires a significant amount of money to purchase or maintain. Other synonyms include "pricey" and "high-priced."
They are synonyms.
The superlative for costly is "most costly" or "costliest."
Synonyms
Yes, costly is an adjective. E.g. It was a costly mistake. (One that was expensive to fix, or that led to other bad consequences.)
Relative and kin are synonyms.
It should be most costly.