The word "in consequential" refers to something that has little or no significance or importance. Its antonyms are words that represent the opposite meaning, such as "crucial," "essential," "significant," and "meaningful." Other antonyms to consider include "significant," "relevant," "relevant," "influential," "substantial," and "vital." All these words are used to convey the importance, impact, or relevance of something. For instance, a crucial decision can have significant consequences, while a vital contribution can make a substantial impact. Therefore, when trying to convey the opposite of "in consequential," these antonyms can be used to emphasize the importance or relevance of something.