The quality or state of being absolute; complete, unconditional, or free from any limitation or qualification.
From absolute (from Latin absolutus 'finished, loosened') plus -ness (suffix forming abstract nouns). The absolute/absolute- root means 'loosened free' suggesting completeness.
Absoluteness fascinates philosophers because it's nearly impossible to find in real life—even 'absolute zero' turns out to be unreachable, making absoluteness more of a useful fiction than an actual state of being.
Complete word intelligence in one call. Free tier — 50 lookups/day.