Adjective upbeat has 1 sense
  1. cheerful, pollyannaish, upbeat - pleasantly (even unrealistically) optimistic
    Antonym: pessimistic (indirect, via optimistic)
,Noun upbeat has 2 senses
  1. wellbeing, well-being, welfare, upbeat, eudaemonia, eudaimonia - a contented state of being happy and healthy and prosperous; "the town was finally on the upbeat after our recent troubles"
    --1 is a kind of prosperity, successfulness
    --1 has particulars: fool's paradise; health, wellness
  2. upbeat - an unaccented beat (especially the last beat of a measure)
    --2 is a kind of
    rhythm, beat, musical rhythm