Which term describes something that is drearily commonplace or trite?

The term that best describes something that is drearily commonplace or trite is "banal." This word specifically conveys the sense of something lacking in originality or freshness, often to the point of being dull or tiresome. It is frequently used in contexts where an idea, theme, or expression has become so overused that it no longer evokes strong feelings or interest.

While the other options such as "common," "ordinary," and "unoriginal" may seem related, they do not capture the same negative connotation that "banal" does. "Common" and "ordinary" can refer to things that are usual or typical without necessarily implying a lack of value or creativity. "Unoriginal" indicates something that lacks originality but does not inherently connect to the dreary or dull aspect that "banal" encompasses. Therefore, "banal" is the most precise term for describing something that is not only commonplace but also evokes a sense of weariness or boredom.