Writer's block is a condition, in which an author loses the ability to produce new work. The condition varies widely in intensity. It can be trivial, a temporary difficulty in dealing with the task at hand. At the other extreme, some "blocked" writers have been unable to work for years on end, and some have even abandoned their careers. It can manifest as the affected writer viewing their work as inferior or unsuitable, when in fact it could be the opposite.
Writer's block may have many or several causes. Some are essentially creative problems that originate within an author's work itself. A writer may run out of inspiration. The writer may be greatly distracted and feel he or she may have something that needs to be done beforehand. A project may be fundamentally misconceived, or beyond the author's experience or ability.
Other blocks, especially the more serious kind, may be produced by adverse circumstances in a writer's life or career: physical illness, depression, the end of a relationship, financial pressures, a sense of failure. The pressure to produce work may in itself contribute to a writer's block, especially if they are compelled to work in ways that are against their natural inclination, i.e. too fast or in some unsuitable style or genre. In some cases, writer's block may also come from feeling intimidated by a previous big success, the creator putting on themselves a paralyzing pressure to find something to equate that same success again.