IPA: /ˈblækli/
KK: /ˈblækli/
In a way that is dark or gloomy.
The sky blackly loomed over the city as the storm approached.
Blackly → It is formed from "black" (from Old English "blæc", meaning dark or the color black) and "-ly" (meaning in a manner of). The word "blackly" means in a manner that is dark or black.
Think of the word 'black' to remember that 'blackly' describes something done in a dark or black manner.