Hubris is a noun that refers to excessive pride or self-confidence.

Our word of the day comes from the Ancient Greeks and began to appear is English around the late 19th and early 20th century. The word may be used to refer to the excessive self-confidence of an individual or a group of individuals, for example: We had a number of great players on our high school team. But our collective hubris made us overly confident and we were beaten in the finals.