What term describes something that brings ruin or downfall?

The term "disastrous" aptly conveys the idea of something that leads to ruin or downfall. It describes an event or outcome that is calamitous or harmful in nature, often associated with significant loss or destruction. This term captures the essence of a situation that causes severe negative consequences, reflecting a state of failure or misfortune.

In contrast, the other terms have different meanings. "Salvageable" refers to something that can be saved or recovered, suggesting a more positive outcome. "Fortunate" indicates being lucky or having good fortune, which is the opposite of experiencing ruin. "Adventurous" pertains to being willing to take risks or embark on exciting undertakings, often associated with positive experiences rather than downfall. Thus, "disastrous" is the most appropriate choice for describing a scenario that brings about ruin or downfall.