zestful - n.
1 piquancy; a stimulating flavour or quality.
2 a keen enjoyment or interest. b (often foll. by for) relish. c gusto (entered into it with zest).
3 a scraping of orange or lemon peel as flavouring.

zestful adj. zestfully adv. zestfulness n. zesty adj. (zestier, zestiest). [F zeste orange or lemon peel, of unkn. orig.]