"Toothily" is an adverb that means with the teeth showing or in a way that reveals the teeth. There are several synonyms to describe this action, such as grinningly, smilingly, or smirkingly. "Grinningly" indicates a broad, happy smile that often shows teeth. "Smilingly" refers to a friendly or pleasant smile. "Smirkingly" represents a smug or mocking grin that shows satisfaction in one's actions. Other potential synonyms include beamingly, chucklingly, or snickeringly, depending on the nature of the smile or the emotion behind it. When used correctly, knowing these synonyms can help bring clarity and precision to your writing.