Which word best describes something that is forceful and brief?

The term that best describes something that is forceful and brief is "pithy." This word is often used to characterize language or communication that conveys a lot of meaning in a concise manner, making it impactful and effective. Pithy statements are typically characterized by their brevity alongside a strong emotional or intellectual resonance, which aligns perfectly with the description given in the question.

In contrast, the other choices do not fit the description as well. "Pomp" refers to splendor and magnificence, often in a grand display, which does not imply brevity or forcefulness. "Peccadillo" denotes a minor fault or sin, which is unrelated to the characteristics of being brief or forceful. "Petulant" describes a person who is childishly sulky or bad-tempered, which again does not capture the essence of being concise and impactful. Therefore, "pithy" is the most appropriate word to describe something that is both forceful and brief.