hollow

[1]	excavate , dig
[2]	hollow out , core out
[3]	excavate , dig (out/up) , gouge , scoop , furrow , dredge

[1]	holler
[2]	hole
[3]	hole , cavity , cavern , crater , basin , depression , excavation , pit , trough , furrow , indentation , dent , impression , valley , dale , dell , glen , dip

adj.

[1]	vacant , empty , void , unfilled
[2]	sunken , concave , indented , dented , sunken , recessed , depressed
[3]	hungry , ravenous , starved , empty , famished
[4]	insincere , false , hypocritical , sham , artificial , counterfeit , feigned , fraudulent , spurious , deceitful , mendacious , deceptive , cynical
[5]	empty , futile , costly , Pyrrhic , worthless , vain , unavailing , bootless , fruitless , profitless , unprofitable , valueless , ineffective , pointless , senseless , meaningless
[6]	muffled , dull , flat , low , sepulchral , toneless
[7]	empty , vacuous