Crowning glories are often used to describe something grand, but this term also has antonyms that may be used to contrast a particular subject or instance. The antonyms for the phrase crowning glories are insignificance, mediocrity, and unremarkableness. The latter three terms denote a lack of grandness, importance or achievement. An example of their usage can be in sports, where an athlete may experience a series of unremarkable performances before they finally achieve their crowning glory. In summary, while crowning glories are celebrated moments of greatness, antonyms reflect the opposite or lack thereof; they are ordinary or insignificant events that do not stand out.