The antonyms for the word "by-plays" could include the terms "seriousness," "solemnity," and "gravity." By-plays typically refer to minor or less significant events or activities that occur alongside something else, such as a main storyline. In contrast, seriousness, solemnity, and gravity suggest a sense of weight and importance, evoking a more significant and meaningful experience. These antonyms could be used in contrast to by-plays in writing or speech, whether to emphasize the importance of a particular event or to minimize the influence of less essential elements.