General importance:
* 大切 (taisetsu): This is the most common and versatile word for "important." It can be used in a variety of situations and conveys a sense of value and significance.
* 重要 (jūyō): This word emphasizes the crucial nature of something and is often used in formal settings.
Specific importance:
* 重大 (jūdai): This word implies great importance or seriousness.
* 緊要 (kin'yō): This word conveys urgency and implies that something is very important and needs immediate attention.
* 必須 (hissu): This word means "essential" or "indispensable."
* 不可欠 (fukaketsu): This word means "necessary" or "essential."
Other related words:
* 意味深い (imigibukai): This word means "meaningful" or "significant."
* 価値がある (kachigaaru): This phrase means "valuable" or "worthwhile."
The best word to use will depend on the specific context and the desired level of formality.