あっけ呆気akkeないnai
1.

Describes a situation or event that concludes in a way that feels sudden or unexpectedly simplistic, leaving the observer with a sense of dissatisfaction or unfulfilled expectations.

2.

Indicates an experience that lacks depth or complexity, resulting in a feeling that something important was missed or not sufficiently explored.

3.

Refers to a moment or outcome that is perceived as too brief or rapid, causing disappointment due to its abruptness and lack of development.

4.

Conveys a sentiment that the ending or resolution of something feels inadequate or lacking substance, leading to a sense of emptiness or letdown.

Example:

休暇はいつもあっけなく終わる。