hol·low / ˈhälō/ • adj. 1. having a hole or empty space inside: each fiber has a hollow core. ∎  (of a thing) having a depression in its surface; concave: hollow cheeks. ∎  (of a sound) echoing, as though made in or on an empty container: a hollow cough.2. without significance: the result was a hollow victory. ∎  insincere: a hollow promise.• n. a hole or depression in something: a hollow at the base of a large tree. ∎  a small valley: the house fell behind as they climbed out of the hollow.• v. [tr.] form by making a hole: a tunnel was hollowed out in a mountain range. ∎  make a depression in.PHRASES: beat someone hollow defeat or surpass someone completely or thoroughly. in the hollow of one's hand entirely in one's power: great events lay in the hollow of his hand.DERIVATIVES: hol·low·ly adv.hol·low·ness n.

hollow adj. XII. ME. holʒ, holu, inflected hol(e)we, attrib. use of OE. holh hole, cave, obscurely rel. to hol HOLE.
Hence vb. XV, sb.