upbeat

up|beat /'ʌpbiːt/ (upbeats)
1 [ADJ] usu ADJ n
If people or their opinions are upbeat, they are cheerful and hopeful about a situation. (INFORMAL)
The Defense Secretary gave an upbeat assessment of the war so far...
Neil's colleagues say he was actually in a joking, upbeat mood...
= positive
2 [N-COUNT]
In music, the upbeat is the beat before the first beat of the bar.
≠ downbeat