Exhilaration exclamation (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
whee
(Other definitions for whee that I've seen before include "Expression of delight" , "Exclamation of excitement when going fast" , "Cry from someone going downhill fast?" , "I'm going downhill, fast!" , "Exuberant cry" .)