Etymology 1640–50, from Early Modern French foible (“feeble”) (contemporary French faible). Doublet of feeble.
1
In plural A quirk, idiosyncrasy, frailty, or mannerism; an unusual habit that is slightly strange or silly.
Try to look past his foibles and see the friendly fellow underneath.
He knew that this was like the sudden impulse of a madman—incongruous even with his habitual foibles.1871–1872, George Eliot [pseudonym; Mary Ann Evans], chapter XV, in Middlemarch […], volume (please specify |volume=I to IV), Edinburgh; London: William Blackwood and Sons, →OCLC, book II:
3 more examples
Marguerite Blakeney was, above all, a woman, with all a woman’s fascinating foibles, all a woman’s most lovable sins.1905 January 12, Baroness Orczy [i.e., Emma Orczy], The Scarlet Pimpernel, popular edition, London: Greening & Co., published 20 March 1912, →OCLC:
They made up for the respect with which unconsciously they treated him by laughing at his foibles and lamenting his vices.1915, W[illiam] Somerset Maugham, chapter XLV, in Of Human Bondage, New York, N.Y.: George H[enry] Doran Company, →OCLC:
Final fillip in the Vice-President's study has been a boning up on Premier Khrushchev's favorite foible, proverbs. The bibulous Russian leader likes to throw out homely homilies in his speeches and conversations[…]1959 July 24, “An Ounce of Prevention”, in Meriden Record, page 6:
2
A weakness or failing of character.
Jesus is reverenced as the one man who has lived unspotted by the world, free from human foibles, able to redeem mankind by his example.1932, William Floyd, The Mistakes of Jesus:
The good Fencing-maſters, in France eſpecially, when they preſent a Foyle or Fleuret to their Scholars, tell him it hath two Parts, one of which he calleth the Fort or ſtrong, and the other the Foyble or weak […]a. 1648, Edward Herbert, 1st Baron Herbert of Cherbury, The Life of Edward Lord Herbert of Cherbury, page 46