Other forms: foibles
If you repeat foible out loud enough times, it sounds so funny that you can laugh at it and maybe remember to laugh at the odd and distinctive weaknesses of others — the foible or two or a hundred that we all have.
Sometimes a foible helps make a person who they are, even if the foible, or weakness ("feeble" is a close relative), is a little odd. Synonyms for foible in a negative sense are "failing," "shortcoming," and in a more positive sense "quirk," "eccentricity." It can likewise be annoying or endearing. Most people have a foible, or idiosyncrasy, that stands out to others, but interestingly, a person rarely sees his or her own characteristic foible.