油断

Etymology
Unclear, with multiple theories.
 * From the story of the in the  ; see.
 * Sound change from.
 * There is a lamp in  that has been alight since the time of , its founder, and  refers to not letting it go out.
 * There is a lamp in  that has been alight since the time of , its founder, and  refers to not letting it go out.

The term is not understood in other parts of the Sinosphere.

Noun

 * 1) being unprepared

Verb

 * 1) to be caught off-guard; to be unprepared