1.
indispensable; essential; vital
Absolutely necessary; cannot be done without. Used for things or factors that are critical to success or functioning.
水は生命に不可欠だ。
Water is essential for life.
成功には努力が不可欠だ。
Effort is indispensable for success.
スマホは現代生活に不可欠なものになった。
Smartphones have become essential to modern life.
FORMATION:
不 (not) + 可 (possible) + 欠 (lack/missing)
Literally 'cannot be lacking.'
GRAMMAR:
- 〜に不可欠だ - is essential for ~
- 不可欠な + noun - essential (noun)
- 不可欠の + noun - essential (noun) [formal]
COLLOCATIONS:
- 不可欠な要素 - essential element
- 不可欠な存在 - indispensable presence
- 〜には不可欠 - indispensable for ~
REGISTER:
Formal/written style. In casual speech, 必要 or なくてはならない are more common.
SIMILAR WORDS:
- 必須 - essential, required
- 必要 - necessary
- 欠かせない - indispensable (colloquial)