The word "more shuddering", which conveys extreme fear and terror, can be described by numerous antonyms that reflect different levels of calmness and tranquility. Some possible antonyms for this term include: calm, serene, untroubled, undisturbed, unconcerned, relaxed, tranquil, peaceful, composed, and placid. These words denote the opposite state of being that is characterized by a lack of intense emotion or disturbance. They suggest a sense of stability and confidence, and imply that there is no reason to fear or dread. By using these antonyms, one can create a contrasting mood that will emphasize the power and impact of the original term "more shuddering".