The quality or state of being unable to cause harm or damage.
From harmless (harm + -less) + -ness (abstract noun suffix). This formation follows the standard English pattern of converting adjectives to abstract nouns representing their essential qualities.
Harmlessness is legally and morally important—it's why a toy that looks dangerous but is actually harmless gets different treatment than something genuinely dangerous, which is crucial for product safety regulations.
Complete word intelligence in one call. Free tier — 50 lookups/day.