While both "unimportant" and "trivial" suggest something lacking in significance, there's a subtle difference between them. "Unimportant" simply means something that doesn't matter or isn't significant in a given context. "Trivial," however, implies not only a lack of importance but also a sense of being insignificant or petty, often implying something is small, commonplace, or of little value. Think of it this way: something unimportant might be a minor detail, whereas something trivial is often considered childish or inconsequential.

For example, "The color of the car is unimportant." (Meaning: The color of the car doesn't matter; it's not a crucial factor.)

Translation: The color of the car is not a significant factor.

On the other hand, "His concerns were trivial." (Meaning: His concerns were petty, insignificant, and not worth worrying about.)

Translation: His worries were small and inconsequential.

Another example: "Missing a single class is unimportant, but missing many classes is a serious problem." (Meaning: A single absence is a minor detail, while multiple absences are significant.)

Translation: One missed class is insignificant, but many missed classes constitute a serious issue.

In contrast, "Her worries about a small scratch on her phone were trivial." (Meaning: Her worries were insignificant and excessive given the issue.)

Translation: Her concerns over a minor scratch on her phone were petty and undeserving of worry.

These examples show the difference: "unimportant" simply means not important, while "trivial" adds a sense of pettiness or insignificance to the lack of importance. The choice of word depends on the nuance you wish to convey. Happy learning!