/ Thesaurus / G Synonyms of gbu 28 Find synonyms for: Noun1. Bunker Buster, Guided Bomb Unit-28, GBU-28usage: a 5,000 pound laser-guided bomb that can be programmed to penetrate to a given depth before exploding; used to penetrate hardened underground facilitiesWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: mongrel Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language