Despair in common usage is the condition of having abandoned hope.
Existentialist philosophers use despair in the specific sense of having to make choices in a world in which all knowledge is uncertain - see Existential despair.
Despair is also a character from the Sandman series of Comic books by Neil Gaiman - see Despair (Sandman).
Despair, Inc. is an Internet business known for having a trademark on the :-( emoticon and selling "Demotivators" products.