Home › Words › R › ridgelessnessridgelessnessridgelessness means absence of ridges.Among words judged in Lexicurio's Arena, ridgelessness ranks #14,679 of 42,747 for Qualifying.EtymologyFrom ridgeless + -ness.nounAbsence of ridges.Definitions & examples from Wiktionary (CC BY-SA 3.0).