lightheadedness

noun

Etymology: From light-headed (adjective) (any sense) + -ness (suffix forming nouns).

The state or quality of being light-headed; dizziness or faintness; flightiness; wandering; delirium.
“The lightheadedness passed once I lay down.”
“The effects caused by inhaling nitrous oxide gas, such as lightheadedness and euphoria, can be felt within seconds.”