mumpsimus /mumpˈsi-məs/

1. A view or opinion stubbornly held, even when shown to be misguided
2. A person holding such a view, or one adhering stubbornly to old ways

• factionalizing
• factionaries
• factionary
• factionist
• factionists
• factions
• factious
• factiously
• factiousness
• factiousnesses
• factis
• factitious
• factitiously
• factitiousness
• factitiousnesses
• factitive
• factive
• factoid
• factoids
• factor
• factor 8
• factorabilities
• factorability
• factorable
• factorage