niaiserie
/nɪˈeɪz(ə)ri/(also niaisery) Now chiefly literary
noun
Simplicity; foolishness; (in later use) especially an instance of this.
Origin
Mid 17th century; earliest use found in John Sergeant (1623–1707), Roman Catholic controversialist and philosopher. From French niaiserie from niais simple, foolish + -erie.