hollow

adj. 1 a having a cavity; not solid. B sunken (hollow cheeks). 2 (of a sound) echoing. 3 empty; hungry. 4 meaningless (hollow victory). 5 insincere (hollow laugh). n. 1 hollow place; hole. 2 valley; basin. v. (often foll. By out) make hollow; excavate. adv. Colloq. Completely (beaten hollow).  hollowly adv. Hollowness n. [old english]

a. Having an empty space or cavity, natural or artificial, within a solid substance; not solid; excavated in the interior; as, a hollow tree; a hollow sphere.