The phrase "wrought into lather" refers to a state of extreme agitation, excitement, or anger. Its antonyms, therefore, would be words that denote calmness or tranquility. Some possible antonyms for this phrase might include "calm," "serene," "composed," "placid," "unflappable," "collected," "relaxed," or "peaceful." These words suggest a state of mind that is in sharp contrast to the frenzied or tumultuous state often implied by "wrought into lather." Other possible antonyms might include more specific words that suggest an absence of the particular emotion or circumstance that might lead someone to become agitated or excited, such as "indifferent," "disinterested," or "unconcerned.