When we hold grimly, we're typically gripping onto something tightly, usually out of fear, determination, or desperation. A few synonyms that capture the essence of this phrase include clutching, gripping, grasping, and clinging. Each of these words conveys a sense of holding onto something with great force, as if we're trying to maintain our grip no matter what happens. Other similar terms might include clinging onto, hanging onto, or digging in. Regardless of which word we use, the message conveyed is one of strength, resilience, and determination in the face of adversity.