What does 'trifling' mean in terms of importance?

The term 'trifling' refers to something that is of little importance or value; it conveys a sense of being trivial, insignificant, or frivolous. In this context, selecting the meaning aligned with 'not significant; frivolous' captures the essence of the word accurately.

In contrast, the other options suggest a degree of importance or seriousness that directly contradicts the meaning of 'trifling.' For instance, terms like 'significant and crucial' and 'important and serious' directly imply a level of importance that 'trifling' negates. Similarly, 'highly valuable' indicates worth or importance, which is the opposite of what 'trifling' conveys. Thus, the correct choice accurately reflects the word's definition, underscoring its connotation of insignificance.