Picture an egg. If you drop it on the floor, it will break easily. That is an example of something that is fragile. Now think of something that's the opposite of fragile. You might think of objects like rocks, metal, pieces of wood, etc. These objects will break but break to a lesser extent than an egg when dropped. This is the definition of robust, not fragile.
Antifragility, as defined by Nassim Taleb in the book with the same title, is a property of objects that become stronger when subjected to stress, disorder, etc. In the next few posts, I'll give further examples of antifragility and how it can improve your investment portfolio.