Emily Dickinson Lexicon

FOI'BLE, n. [Fr. foible, weak. See Feeble.]

A particular moral weakness; a failing. When we speak of a man's foible, in the singular, which is also called his weak side, we refer to predominant failing. We use also the plural, foibles, to denote moral failings or defects. It is wise in every man to know his own foibles.