a. [f. L. fallāci-a (see FALLACY) + -OUS. Cf. F. fallacieux. In early use it appears with sense derived from that of the sb.; subsequently (in accordance with the usual tendency of adjs. in -ACIOUS) it came to be taken as the representative of L. fallax.]
1. Of an argument, syllogism, etc.: Containing a fallacy.
1509. Hawes, The Pastime of Pleasure, XI. xx.
| Seven sophyms full hard and fallacyous | |
| Thys ydre used in preposicion | |
| Unto the people. |
1651. Baxter, Plain Scripture Proof of Infants Church-membership and Baptism, 228. I undertake to prove every Argument of his to this point to be vain and fallacious, to any man that will dispute it.
1788. Reid, Aristotle’s Log., v. § 3. 115–6. Such fallacious syllogisms are considered in this treatise, in order to make a defendant more expert in the use of his defensive weapons.
1864. Bowen, Logic, ix. 294. Those fallacious reasonings which are correct in Form, since the Conclusion is logically drawn, but are faulty in Matter, either from some error or undue assumption in the Premises, or some mistake as to the point to which the argumentation ought to be directed.
2. † a. Of persons: Deceitful (obs.). b. Of things: Deceptive, misleading.
a. 1663. Cowley, The Complaint, viii.
| Teach me not then, O thou fallacious Muse, | |
| The Court, and better King t’ accuse. |
1769. Burke, Observations on a Late State of the Nature, Wks. 1842, I. 82. I am willing from a strain of candour to admit that this author speaks at random; that he is only slovenly and inaccurate, and not fallacious.
b. 1651. Biggs, New Disp., ¶ 305. Surely medicine is not a naked word, the very word is not idle here: a meer word without a sense, much lesse a fallacious word, signifying contrary to what it pretends.
1772–84. Cook, Voy. (1790), VI. 2024. As they had no thermometer with them, they could only form their judgment of it from their feelings; which, from the warm atmosphere they had quitted, must have been a very fallacious method of judging.
1856. Froude, Hist. Eng. (1858), II. x. 434. No evidence is more fallacious than that which rests upon isolated facts.
3. That causes disappointment; mocking expectation, delusive.
1667. Milton, P. L., IX. 1046.
| Soon as the force of that fallacious Fruit, | |
| That with exhilerating vapour bland | |
| About their spirits had plaid. |
1741. C. Middleton, Cicero, II. X. 385. If we have been drawn away by false and fallacious hopes, let us turn again into the way.
1877. Sparrow, Sermons, i. 11. Nor is it a deceitful joy—a fallacious peace.
