Beavers so enthusiastic? (5)
I believe the answer is:
eager
This clue might be a double definition.
'beavers so' is the first definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?
'enthusiastic?' is the second definition.
(similar in meaning)
Can you help me to learn more?
(Other definitions for eager that I've seen before include "Keen, avid" , "Enthusiastic, full of desire" , "passionate" , "Keenly expectant" , "Impatient" .)