Keenly is an adverb that describes an action done with eagerness or enthusiasm. It can also mean having a sharp or intense perception. Synonyms for keenly include avidly, passionately, eagerly, intensely, fervently, ardently, enthusiastically, and zealously. Each of these words carries similar connotations of being deeply committed or invested in a task or goal. Keenly can also be replaced with other adverbs, such as acutely, keen, sharply, or astutely. By using different synonyms for keenly, a writer can vary their word choice and create more engaging and dynamic sentences.