empty

(usually plural) A container, especially a bottle, whose contents have been used up, leaving it empty.

"Put the empties out to be recycled."

To make empty; to void; to remove the contents of.

"The cinema emptied quickly after the end of the film."

Of a river, duct, etc: to drain or flow toward an ultimate destination.

"Salmon River empties on the W shore about 2 miles below Bear River."

Devoid of content; containing nothing or nobody; vacant.

"an empty purse; an empty jug; an empty stomach"

Containing no elements (as of a string, array, or set), opposed to being null (having no valid value).

Free; clear; devoid; often with of.