The word "seethings" means to boil or churn, and there are many synonyms that convey a similar sense of agitation or turmoil. Some examples include: roil, boil, bubble, fume, ferment, rage, swirl, surge, blaze, seethe, and simmer. Each of these words offers a slightly different nuance, whether it's the intensity of the feeling or the physical movement that's being described. For instance, "roil" brings to mind deep, turbulent waters, while "simmer" suggests a quieter but still persistent agitation. All of these synonyms can be useful in different contexts, whether you're talking about emotions, weather patterns, or physical processes.