Something that interferes with movement or progress.
Example:
Her poorly developed verbal ability was the most serious impediment to her advancement.
Impediment comes from a Latin verb that meant "to interfere with" or "to get in the way of progress" -- perhaps by catching one's feet. In English, impediment still suggests an obstruction or obstacle along a path; for example, a lack of adequate roads and bridges is an impediment to economic development. Impediments usually get in the way of something we want. We speak of an impediment to communication, marriage, or progress, but something that slows the process of aging, disease, or decay isn't usually called an impediment.