オープンoopun

1. noun, suru verb, intransitive verb, transitive verbopening (a new store, golf course, runway, etc.)
   新あたらしいショッピングモールが街まちのはずれにオープンした。↗

   A new shopping mall opened on the edge of town.
2. na-adjectiveopen; frank; approachable; open-hearted
3. prenominal modifieropen (car, collar, tournament, etc.)

• Synonym公然こうぜんWrittenOpen and unconcealed, as in 「公然の秘密」; written/formal prose, and often carries a nuance of brazen openness.
• Synonym開くあくNeutralThe most versatile verb: to open, bloom, or open for business, as in 「店を開く」; 「オープン」 is mostly a noun or suru-verb.
• SynonymおおっぴらCasualColloquial for doing something openly and without reserve, as in 「大っぴらに話す」; 「オープン」 leans toward frankness and openness of heart.
• Related開催かいさいNeutralFor holding conferences and events, as in 「大会を開催する」; stresses hosting, while 「オープン」 stresses opening a business or opening up.
• Related開放かいほうNeutralFor opening doors and windows or opening a place to the public, as in 「校庭を開放する」; stresses allowing people in.
• RelatedひらきNeutralA noun for opening, gaps, or split-and-dried fish, as in 「アジの開き」; it does not mean opening for business.
• RelatedひらくNeutralThe most versatile verb: to open, bloom, or open for business, as in 「店を開く」; 「オープン」 is mostly a noun or suru-verb.
• RelatedパブリックNeutralLoanword meaning public and open to everyone, as in 「パブリックスペース」; it does not mean opening for business.
• AntonymクローズNeutralLoanword for closing or ending business; the opposite of 「オープン」 in the opening-for-business sense.
• Antonym閉鎖へいさNeutralClosing down or ceasing operation, as in 「工場閉鎖」; the opposite of 「オープン」's opening and opening-up senses.

For a new store opening or a frank, open attitude, use 「オープン」. Use 「開催」 for holding events and 「開放」 for opening a place to the public; 「開く」 is the all-purpose verb. Opposites: 「クローズ」 (closing a business) and 「閉鎖」 (shutting down).

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

1. 公開こうかい。公表こうひょう。
2. 開店かいてん。開業かいぎょう。
3. 開放的かいほうてきなさま。