How to say "costly" in Japanese

• 高価こうかJLPT N3approx.Common
  na-adjective, nounCovers the everyday sense of 'costly': carrying a high price. Use it for expensive items such as jewelry, clothing, or a valuable gift; this is the word you will almost always want.
  そんな高価こうかな本ほんは買かえないよ。↗

  I can't buy a book this expensive.
• 物入りものいり
  na-adjectiveA less common word meaning costly or expensive in the sense of requiring considerable expense, often for upkeep or a project. Because of its limited use, it is seldom the word learners need for 'costly'.

For the usual sense of 'costly' meaning expensive, use 高価; 「物入り」 describes something costly to keep up or requiring heavy expenses, and is a less common choice learners will rarely need.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 高価こうかhighly priced
• 物入りものいりcostly