An impediment is anything that slows or blocks progress. It can refer to a physical thing, like a fallen tree in the road, or something more intangible, like how your short stature is an impediment to becoming a professional basketball player.
See the pedi in there? Pedi means "feet" and hundreds of years ago, the word impediment referred to shackling one's feet. Now its use has broadened considerably. An impediment is something that blocks or impedes your path. There's no end to the things in your life that can be considered impediments: your small bank account, your terrible childhood, your country's economic malaise — any one of these could be considered an impediment in your quest for happiness.