a contented state of being happy and healthy and prosperous
"the town was finally on the upbeat after our recent troubles"
An unaccented beat at the start of a musical phrase.
"The conductor raised his baton to emphasize the upbeat before launching into the main melody."
pleasantly (even unrealistically) optimistic
"Despite the looming deadline and missing data, she remained upbeat about our chances of finishing on time."
Having a fast pace, tempo, or beat.
"The DJ cranked up the volume so the upbeat track had everyone dancing by the second chorus."