fallax

English edit

Borrowed from Latin fallax (“deceptive”).

fallax (plural fallaxes)

(obsolete) cavillation; petty criticism
- a. 1556, Thomas Cranmer, An Answer to a Crafty and Sophistical Cavillation devised by Stephen Gadiner:
  First, after the sum of my fourth book, collected as pleaseth you, at the first dash you begin with an untrue report, joined to a subtle deceit or fallax, saying that my chief purpose that evil men receive not the body and blood of Christ in the sacrament.

From fallō (“I deceive”) +‎ -āx (“inclined to”).

fallāx (genitive fallācis, comparative fallācior, superlative fallācissimus, adverb fallāciter); third-declension one-termination adjective

deceptive, deceitful
- 405 CE, Jerome, Vulgate Proverbs.26.28:
  Lingua fallāx nōn amat vēritātem: et ōs lūbricum operātur ruīnās. [adjective]
  1752 translation by Douay-Rheims, Challoner rev.
  A deceitful tongue loveth not truth: and a slippery mouth worketh ruin.
fallacious, spurious

Third-declension one-termination adjective.

Case / Gender	Masc./Fem.	Neuter	Masc./Fem.	Neuter
Number	Singular		Plural
Nominative	fallāx		fallācēs	fallācia
Genitive	fallācis		fallācium
Dative	fallācī		fallācibus
Accusative	fallācem	fallāx	fallācēs	fallācia
Ablative	fallācī		fallācibus
Vocative	fallāx		fallācēs	fallācia

“fallax”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
“fallax”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
fallax in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
Carl Meißner, Henry William Auden (1894) Latin Phrase-Book‎^[1], London: Macmillan and Co.
- a fallacious argument; sophism: conclusiuncula fallax or captio