When it comes to expressing something firmly, there are plenty of words to choose from. One synonym for firmly is "securely," which suggests a sense of safety and stability. Another option is "solidly," which conveys a feeling of strength and resilience. Alternatively, "steadfastly" suggests a sense of determination and commitment. "Resolutely" is another synonym that conveys a sense of unwavering resolve, while "decisively" suggests a prompt and confident course of action. Ultimately, there are many words that can be used to express something firmly, each offering a slightly different nuance or shade of meaning depending on the context.