How much fun this is? Very little, you’d say (4)

I believe the answer is:
whee
I'm afraid I can't explain this answer.
Can you help me to learn more?
(Other definitions for whee that I've seen before include "I'm going downhill, fast!" , "Exclamation of excitement when going fast" , "Cry from someone going downhill fast?" , "What fun" , "Exuberant cry" .)
