Definition of "proof"

But the false Fox most kindly played his part, / For whatsoever mother-wit or art / Could work he put in proof. No practice sly, / No counterpoint of cunning policy, / No reach, no breach, that might him profit bring. / But he the same did to his purpose wring.

1591, Edmund Spenser, Prosopopoia: or, Mother Hubbard's Tale, later also published in William Michael Rossetti, Humorous Poems

France I more praise and love; you are, my lord,Yourself for horsemanship much famed; and thereYou shall have many proofs to shew your skill.

c. 1633, John Ford, Love's Sacrifice, Act 1, Scene 1

A given quantity of the spirits was poured upon a quantity of gunpowder in a dish and set on fire. If at the end of the combustion, the gunpowder continued dry enough, it took fire and exploded; but if it had been wetted by the water in the spirits, the flame of the alcohol went out without setting the powder on fire. This was called the proof.

1831, Thomas Thomson, A System of Chemistry of Inorganic Bodies, volume 2

I'll have some proof.

c. 1603–1604 (date written), William Shakespeare, “The Tragedie of Othello, the Moore of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, (please specify the act number in uppercase Roman numerals, and the scene number in lowercase Roman numerals)

It was a grand sentence of Emanuel Swedenborg, which would alone indicate the greatness of that man's perception, — "It is no proof of a man's understanding to be able to confirm whatever he pleases; but to be able to discern that what is true is true, and that what is false is false, this is the mark and character of intelligence."

1841, Ralph Waldo Emerson, “The Over-Soul”, in Essays: First Series

Faith, faith is an island in the setting sunBut proof, yesProof is the bottom line for everyone

1990 October 16, Paul Simon, “Proof”, in The Rhythm of the Saints, Warner Bros.

But the chaste damzell, that had never priefe / Of such malengine and fine forgerye, / Did easely beleeve her strong extremitye.

1590, Edmund Spenser, “Book III, Canto I”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie

And these men scour the printed proof for error, blunder, and misspelling.

2010, Andrea Levy, The Long Song, Tinder Press (2017), page 382

Till that Bellona's bridegroom, lapped in proof

c. 1606 (date written), William Shakespeare, “The Tragedie of Macbeth”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, (please specify the act number in uppercase Roman numerals, and the scene number in lowercase Roman numerals)

And opportunity I here have had / To try thee, ſift thee, and confeſs have found thee / Proof againſt all temptation as a rock / Of Adamant, and, as a Center, firm / To the utmoſt of meer man both wiſe and good, / Not more; […]

1671, John Milton, “The Fourth Book”, in Paradise Regain’d. A Poem. In IV Books. To which is Added, Samson Agonistes, London: […] J. M[acock] for John Starkey […], page 130, lines 528–533

This was a good, ſtout proof article of faith, pronounced under an anathema, by the venerable fathers of this philoſophick ſynod.

1790, Edmund Burke, “Reflections on the Revolution in France”, in The Works of The Right Honourable Edmund Burke, volume 5, published 1803, page 426

The French cavalry, in proof armour, repeatedly charged our squares, their cannon opening chasms; but the British infantry, though greatly diminished, were inflexible and impenetrable to the last.

quoted in 1818, Christopher Kelly, History of the French Revolution and of the Wars produced by that Memorable Event