IPA: /ˈzɛstləs/
KK: /zɛstləs/
Not having energy or enthusiasm; dull and lifeless.
After a long week at work, I felt zestless and unmotivated to go out.
Comparative: more zestless
Superlative: most zestless
Zestless → It is formed from "zest" (from Old French *zeste*, meaning a piece of citrus peel used for flavor) and "-less" (meaning without). The word "zestless" means lacking zest or enthusiasm.
Think of 'zest' as the flavor or excitement in life, and when something is 'zestless', it means it is without that flavor or enthusiasm.