Optimistic conductor may begin with this
I believe the answer is:
upbeat
'optimistic' is the definition.
(similar in meaning)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for upbeat that I've seen before include "Cheerful and encouraging, like lively music" , "Cheerfully optimistic" , "Optimistic - anacrusis" , "Optimistic, positive" , "Heartening" .)