gbu-28 g. b. shaw • gc · · · Info · Definitions · Characters · · gbu-28 · · Text Common · · Latin · · Scripts 6 · · Length 1 · · Syllables Definitions · · · (noun) a 5,000 pound laser-guided bomb that can be programmed to penetrate to a given depth before exploding; used to penetrate hardened underground facilities. Synonyms: Bunker Buster, Guided Bomb Unit-28, GBU-28. · · Noun Definition 1 Characters · · - hyphen-minus U+002D 2 digit two U+0032 8 digit eight U+0038 b latin small letter b U+0062 g latin small letter g U+0067 u latin small letter u U+0075