Phosphorescently is an adverb that describes something that emits light gradually after exposure to a particular light source. Some possible synonyms for this word include luminescently, radiantly, iridescently, resplendently, and effulgently. These words all suggest a glowing or shimmering quality, and can be used to describe anything from natural phenomena like the Northern Lights to human-made objects like glow-in-the-dark toys. Depending on the context, other possible synonyms might include luminously, brilliantly, glitteringly, or incandescently. When choosing a synonym for phosphorescently, it is important to consider the specific qualities of the light in question and the overall tone or mood of the text.