The word "zest" refers to a strong feeling of enjoyment and enthusiasm. It can be associated with a sense of excitement or vigor in doing something. Additionally, "zest" can also mean the outer peel of citrus fruits, which is often used to add flavor to dishes.
The word "zest" comes from the Old French word "zeste," which means "the peel of citrus fruit". The term entered the English language in the late 15th century, originally referring to the way the peel adds flavor, eventually extending its meaning to represent excitement and enthusiasm in general.