Plural of fellness; multiple instances or types of cruelty, fierceness, or mercilessness.
Standard English plural of 'fellness,' created by adding '-es' to the singular abstract noun. This form would be used when discussing multiple distinct instances of cruel behavior.
The fact that 'fellnesses' is grammatically valid shows how productively English works—even if a word is rarely used, the system of suffixes and pluralization is so consistent that we can instantly understand newly created forms!
Complete word intelligence in one call. Free tier — 50 lookups/day.