na-adjective, noun which may take the genitive case particle 'no', noun
Describes an action or event that happens without warning, often with a nuance of surprise or lack of preparation. Commonly used as an adverb with に.
Suddenly it started raining.
彼は出し抜けに辞表を出した。
He abruptly handed in his resignation.
だしぬけ is a more colloquial way to say 'all of a sudden', while 不意 is slightly more formal and often used in set phrases like 不意打ち.
Standard kanji spelling.
Kana spelling; common in casual writing.
Mixed kana-kanji spelling; less common but still used.
Derived from the continuative form of 出し抜ける, “to take someone by surprise,” and originally denoted an action performed before another person could anticipate it.