Also Inflected form of big biggest big·gest UK/ˈbɪɡ.ɪst/ US/ˈbɪɡ.əst/ common adjective 1. greatest in size of those under consideration Synonymsgreatestlargest Similarlarge WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). CMU Pronouncing Dictionary. WordNet 2.1 Copyright Princeton University. All rights reserved.