ふい不意fui
1.

Describes an occurrence or event that is unexpected and catches someone off guard, often leading to surprise or confusion.

2.

Refers to a situation where something happens abruptly without prior warning, resulting in an immediate reaction or emotional response.

3.

Characterizes experiences that are unforeseen and happen unexpectedly, disrupting normal expectations or plans.

4.

Indicates a sudden change or appearance that occurs without anticipation, which may provoke a sense of bewilderment or alarm.

Example:

砦は不意に攻撃された。

ふいう不意打fuiuchiふいう不意討fuiuchi
1.

An unexpected assault on someone, catching them off guard and not allowing for a counteraction.

2.

A sudden and unanticipated action taken to confront an opponent, often aiming to gain an advantage by exploiting a moment of unpreparedness.

3.

A tactic involving a sudden attack or maneuver that occurs without prior warning, resulting in the target being taken by surprise.

Example:

彼は敵に不意打ちを食わせた。

ふい不意fuini
1.

A manner of occurrence that takes place without any prior indication or warning, catching one off guard.

2.

Describes an event or action that happens quickly and without notice, often leading to surprise or confusion.

3.

Refers to something that happens unexpectedly, creating a sense of abruptness in the situation.

Example:

彼はふいに私たちの話に口をはさんだ。