[1] : WordNet (r) 2.0

upbeat
     adj : pleasantly even unrealistically optimistic syn: cheerful,
            pollyannaish
     n 1: a contented state of being happy and healthy and prosperous;
          "the town was finally on the upbeat after our recent
          troubles" syn: wellbeing, well-being, welfare, eudaemonia,
           eudaimonia ant: ill-being
     2: an unaccented beat especially the last beat of a measure
see also:
cheerful pollyannaish wellbeing well-being welfare eudaemonia 
eudaimonia ill-being 

[2] : Moby Thesaurus II by Grady Ward, 1.0

80 moby thesaurus words for "upbeat":
   great leap forward, leibnizian, advance, advancement, amelioration,
   amendment, arsis, ascent, bar beat, beat, bettering, betterment,
   boost, bout, bright, buoyant, cheerful, chiliastic, circle,
   circuit, couleur de rose, course, cycle, diastole, downbeat,
   encouraging, enhancement, enrichment, eugenics, euthenics,
   favorable, fond, furtherance, headway, heartening, improvement,
   lift, light-hearted, melioration, mend, mending, millenarian,
   millennialistic, offbeat, optimistic, perfectibilitarian,
   perfectionist, pickup, positive, preferment, progress, progression,
   promotion, pulsation, pulse, recovery, restoration, revival,
   revolution, rise, rose-colored, roseate, rosy, rotation, round,
   sanguine, series, spell, sunny, systole, thesis, throb, turn,
   uplift, upping, upswing, uptrend, upward mobility, utopian,
   wheel

Upbeat >> U Words
Upbeat, definition of term: Upbeat
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