Kind of optimistic attitude exhibited by 50% of canids (dogs) (3-2)
I believe the answer is:
can-do
'kind' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for can-do that I've seen before include "Showing willingness to get the job done" , "Positive-thinking" , "Positive" .)