tragic irony

Tragic irony is a form of dramatic irony where the audience knows a character's words or actions will lead to disaster, but the character does not.

The gap between what characters believe and what viewers understand creates tension and pathos.

Oedipus vowing to find his father's killer exemplifies tragic irony—the audience already knows he is the killer.

The term applies beyond theater to real situations where someone's hopeful words are undercut by outcomes the observer can foresee: His confident speech about the company's future was tragic irony—we knew the bankruptcy filing was already prepared.