As an adjective hollow
is (of something solid) having an empty space or cavity inside.
As an adverb hollow
is (colloquial) completely, as part of the phrase beat hollow or beat all hollow.
As a noun hollow
is a small valley between mountains; a low spot surrounded by elevations.
As a verb hollow
is to make a hole in something; to excavate (transitive) or
hollow can be to urge or call by shouting; to hollo.
As an interjection hollow
is .
As a proper noun palm is
.