hollow - noun

a cavity or space in something

a small valley between mountains

a depression hollowed out of solid matter

hollow - verb

• remove the inner part or the core of
• remove the interior of

hollow - adjective

• not solid; having a space or gap or cavity
• as if echoing in a hollow space
• devoid of significance or point

hollow - thesaurus

dig   empty   excavate   hole   holler   vacuous