Darkle is defined as “to grow dark, gloomy” or “to appear dark.” It managed to make it to Dictionary.com's Word of the Day back on September 2, 2011, proving that it may be a word that we should all know. Its origins come from a back-formation of the now obsolete word, “darkling,” which means “to be in the dark.”
Using it in a sentence tends to help, giving it a more poetic sound. A quote from Johann Wolfgang con Goethe's “Faust: A tragedy”: “and the fire-flies wink and darkle, crowded swarms that soar and sparkle, and in wildering escort gather!”
Still, it seems odd that a description such as sparkle needs a direct opposite word. Usually something is either sparkly or it isn't. Would you ever go out of your way to describe something that lacks a sparkle?
