Becoming lightheaded with 気が遠くなる

意識(いしき)がなくなる。正気(しょうき)を失(うしな)う。

To lose consciousness. To lose one's sanity.

Goo Dictionary

The expression 気(き)が遠(とお)くなる literally means “one’s spirit feels distant” or “the mind feels far away”. It is often used to describe feelings of extreme overwhelm, fatigue, or astonishment. Your 気 (spirit) does the action of 遠くなる (to become distant) from you. It can also mean to faint or pass out.

Examples

Dazed by a wristwatch with 気が遠くなる

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