Usage patterns 不ふ 意い の 〈 事こと 〉 an unexpected ~ (event, visitor, etc.)
I was surprised by an unexpected visitor.
不ふ 意い を 食く う to be caught off guard / taken by surprise
I was caught off guard when someone called out to me from behind.
Expressions 不ふ 意い を 打う つ take unawares; make a surprise attack 不ふ 意い を 突つ く take by surprise; catch off guard Related words 突然 is the everyday word for 'suddenly', while 不意 stresses being caught off guard due to a total lack of forewarning.
意外 means 'unexpected' in the sense of contrary to what one expected, while 不意 focuses on the abruptness and absence of any prior notice.
唐突 emphasizes abruptness that feels out of place or ill-timed, whereas 不意 simply describes something happening without warning.
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 .
不意 describes something sudden or unforeseen (as in 不意に or 不意打ち ), whereas 意表 specifically refers to defying someone's expectations, chiefly in 意表を突く .
Word family surprise attack; catching off guard
suddenly; abruptly; unexpectedly
surprise examination; pop quiz
Written forms 不ふ 意い Usage 59%
Standard kanji spelling; high-frequency in news and general use.
ふい Usage 41%
Etymology Compound of 不 (fu, 'not') and 意 (i, 'mind, expectation'), literally meaning 'not in mind' or 'unexpected'. The reading ふい is the on'yomi of both characters.
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