On a sugar rush, say Crossword Clue

 The answer to the crossword clue "On a sugar rush, say" is HYPER.

The word "hyper" can be used as an adjective meaning excited or overexcited. It can also be used as a noun meaning a state of excitement or overexcitement. In the context of the crossword clue, the word "hyper" is being used as an adjective to describe someone who is on a sugar rush.

Here are some examples of how the word "hyper" can be used in a sentence:

The kids were hyper after eating too much candy.

The dog was hyper and ran around the yard.

The patient was hyper and had trouble sleeping.

I hope this helps!