What is another word for zest starting with z?

There isn't a common word starting with "z" that means the same as "zest". However, depending on the context, you could use:

For enthusiasm and excitement:

* Zephyr: (This word is usually used for a gentle breeze, but figuratively it can suggest a lighthearted and invigorating feeling)

* Zip: (This word can imply energy and liveliness)

For flavor and spice:

* Zing: (This word suggests a sharp, pungent, or stimulating taste)

Ultimately, the best alternative will depend on the specific nuance of "zest" you want to convey.