Which term suggests something that is abnormal or irregular?

The term "anomalous" specifically refers to something that deviates from what is standard, normal, or expected, making it the most fitting choice for describing something abnormal or irregular. It is derived from the word "anomaly," which denotes an irregularity or deviation within a set context. For instance, in scientific observations, an anomalous result would be one that doesn't fit the expected pattern, indicating something unusual or out of the ordinary.

In contrast, other terms provided in the options convey different meanings. "Meager" pertains to something that is insufficient or lacking in quantity or quality, while "idyllic" describes something that is extremely happy, peaceful, or picturesque, often relating to idealized scenarios. "Histrionic" refers to exaggerated emotional behavior, typically aimed at attracting attention, rather than indicating irregularity. Thus, "anomalous" accurately captures the essence of abnormality or irregularity among the choices.