When something lasts only briefly, it can be described in different ways. Synonyms for "of short duration" include "brief," "transient," "ephemeral," "fleeting," "momentary," "temporary," and "short-lived." Each word conveys a slightly different nuance of the concept of something that doesn't last very long. "Brief" emphasizes the brevity of the duration, while "transient" suggests a passing nature. "Ephemeral" refers to something that is fleeting and almost invariably coming to an end. "Fleeting" emphasizes the idea of something that passes quickly, while "momentary" implies an even briefer duration. "Temporary" suggests a limited time period, whereas "short-lived" has a slightly more negative connotation of something that doesn't endure for very long.