Similar word to unsustained:

abbreviate, abbreviated, aphoristic, bare, boiled down, breviloquent, brief, compendiary, compendious, compressed, concise, condensed, curtailed, curtate, cut short, cut to the bone, decreased, decurtate, diminished, epigrammatic, fleeting, in a nutshell, laconic, lessened, little, momentary, not protracted, pithy, pointed, precise, sententious, short and sweet, short-lived, short-term, shortened, succinct, summarized, summary, terse, undersized, unprolonged, unsustained