Type of diet you abandoned early, repeatedly! (2-2)
I believe the answer is:
'type' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for yo-yo that I've seen before include "Fluctuate repeatedly" , "Reel-and-string toy" , "Spinning toy" , "Toy that rises and falls" , "produces toy" .)