Home › Words › S › spontaneousnessspontaneousnessspontaneousness means the state or condition of being spontaneous; spontaneity.Among words judged in Lexicurio's Arena, spontaneousness ranks #28,411 of 42,747 for Qualifying.EtymologyFrom spontaneous + -ness.nounThe state or condition of being spontaneous; spontaneity.Definitions & examples from Wiktionary (CC BY-SA 3.0).