Which of the following words is an antonym for "trivial"?

The term "trivial" refers to something that is of little importance or value. In this context, an antonym is a word that conveys the opposite meaning. "Important" signifies something that has significant value or impact, making it a fitting antonym to "trivial."

When we consider the other words, "insignificant," "minor," and "negligible," they all relate to something that is small or of little worth, aligning with the concept of being trivial. Therefore, they cannot serve as proper antonyms since they share a similar meaning to "trivial," while "important" is distinctly opposite in implication, making it the most appropriate choice.