What is the meaning of Hollow?

A small valley between mountains.

A sunken area on a surface.

An unfilled space in something solid; a cavity, natural or artificial.

A feeling of emptiness.

to make a hole in something; to excavate

Having an empty space or cavity inside.

Distant, eerie; echoing, reverberating, as if in a hollow space; dull, muffled; often low-pitched.

Without substance; having no real or significant worth; meaningless.

Insincere, devoid of validity; specious.

Concave; gaunt; sunken.

Pertaining to hollow body position

Completely, as part of the phrase beat hollow or beat all hollow.

To call or urge by shouting; to hollo.

Alternative form of hollo

Source: wiktionary.org