From Edward Gibbon's *Decline and Fall* (1776). Select the word that fits the blank. "In the prosecution of remote wars, the undertaking became every day more difficult, the event more doubtful, and the possession more ______, and less beneficial."

The blank is in a list of degrading qualities: *more difficult*, *more doubtful*, *less beneficial*. The blank parallel must also be **negative**. "Precarious" (uncertain, risky) fits. - "Permanent", "profitable", "valuable" all reverse the negative trend.