Spuriosity

Ye are next to aſſure all Perſons, vvho are ſo kind as to give you Audience, that to prevent the leaſt Suſpicion of Spurioſity, they may ſee every Letter I have ever printed of Mr. Pope’s in his Ovvn Hand-VVriting, […]

Source: wiktionary

So she made Sir John write to the "Times" to command the Chancellor of the Exchequer for the time being to put a tax on long words:— […] A heavy tax on words over four syllables, as heterodoxy, spontaneity, spiritualism, spuriosity, &c.

Source: wiktionary

This is the sort of struggle which proves a man's metal, and declares it sterling or counterfeit. No spuriosity, no charlatanry can stand this fiery alembic of hard-wrought and exquisite calculation, in which one mathematic point or unit misplaced destroys the whole chain of reasoning, and proves the candidate a blunderer.

Source: wiktionary

The supposition that authors have a preternatural ability to detect spuriosity in writing is as false as the comparable belief that their literary practices make them unerring as literary critics.

Source: wiktionary