What term describes the quality of being honest and straightforward in attitude and speech?

The term that describes the quality of being honest and straightforward in attitude and speech is "candor." Candor reflects a willingness to speak openly and truthfully, with an accent on sincerity and openness. A person exhibiting candor is considered to be forthright and transparent, making it a highly valued trait in both personal and professional contexts, where clear communication is essential.

In contrast, brevity refers to the quality of being concise and to the point, which does not relate directly to honesty or straightforwardness. Circumspect describes a cautiousness and careful consideration of potential consequences, often implying hesitation rather than openness. Cogent relates to being clear, logical, and convincing—important for effective arguments but not specifically tied to the quality of honesty or straightforwardness. Thus, "candor" is the apt choice as it captures the essence of honesty and frankness in communication.