Spoiler

A spoilers is information about a text or a performance that may ruin some readers'/viewers' surprise and/or enjoyment if they learn it outside the intended narrative reveal structure.

For instance, revealing the twist ending to a movie, or the identity of the killer in a murder mystery, may spoil some audience member's appreciation of the suspense in its first acquaintance with these stories.

In the context of critical/literary analysis and discussion, the whole of a work may be discussed, inevitably "spoiling" aspects of it for those who want to approach the work de novo, with a blank slate.

Note: FSFwiki policy: Template:FSFwiki:Spoiler Warnings Policy

The concept of (plot) spoilers has been criticized for privileging plot over other elements of works, such as character development, imagery, writing, etc. A waggish feminist might suggest that narrative plot is a patriarchal plot (as in conspiracy), encouraging audiences/readers to believe in a presumed progressive narrative of "change" and "progress", while neglecting critical analysis of power relations, characterization, and beautiful long descriptions of the water-like imagery of lesbian sexuality. But surely that wouldn't be serious and would violate the "Humorless Feminism Rule".

further reading

• Wikipedia spoiler policy and related discussion
• FSFwiki:Spoiler warnings policy