Added 9 October 2026 massiveness noun Categories: Describing WordsRare Words noun ! Definition from WordNet 3.1, Princeton University. More about massiveness at Wordnik → Where our words come from → An unwieldy largeness. The property of being large in mass. Related Words: heftinessheftponderousnessbulkinessponderositylargenessimmensenessimmensitymassinesshypermassivenessmassnessgiganticness Back to today's word