IPA: /ˈdɑr.kli/
KK: /ˈdɑrkli/
In a way that is not bright or is shadowy; often used to describe something that is mysterious or sinister.
The room was darkly lit, creating an eerie atmosphere.
Darkly → It is formed from "dark" (from Old English *deorc*, meaning lacking light or brightness) and "-ly" (meaning in a manner of). The word "darkly" means in a manner that is lacking light or brightness.
Think of the word 'dark' which means lacking light, and remember that 'darkly' describes doing something in a way that is shadowy or dim.