Unsportsmanlike yo-yoing? (3,2)
I believe the answer is:
not on
I'm afraid I can't explain this answer.
Can you help me to learn more?
(Other definitions for not on that I've seen before include "Modern phrase for unacceptable" , "Informally, can't be accepted or tolerated" , "Common expression meaning won't be entertained or tolerated" , "Impractical" , "Definitely inadvisable" .)