What is the origin of nugatory?

Nugatory “of no force or effect” comes from Latin nūgātōrius “worthless, useless,” from the verb nūgārī “to trifle.” Nūgārī, in turn, derives from the plural noun nūgae “trifles, idle talk, frivolities,” which is also the source of nugacious, a synonym of nugatory, and nugacity, a noun that means “insignificance.” While it may seem odd that Latin features nouns such as nūgae that always appear in the plural, English is no stranger to nouns that usually or exclusively appear in plural form. Many objects that contain two component parts, such as pants, trousers, scissors, and shears, are typically limited to the plural, as are certain location-related words, such as headquarters and surroundings. Nugatory was first recorded in English at the turn of the 17th century.