IPA: /ˈziːələsli/
KK: /ˈziləsli/
In a way that shows great enthusiasm or passion for something.
She worked zealously on her project, determined to make it the best it could be.
Zealously → It is formed from "zeal" (from Old French *zel*, meaning fervor or passion) and the suffix "-ously" (meaning in a manner characterized by). The word "zealously" means in a manner characterized by fervor or passionate dedication.
Think of 'zeal' as a strong passion or fervor, and remember that 'zealously' means doing something with that strong passion.