Which of the following terms relates to something unpleasant or causing desire to avoid it?

The term "odious" accurately describes something that is extremely unpleasant or repulsive, often provoking a strong desire to avoid it. This word stems from the Latin root "odiosus," meaning "hateful," and is frequently used to refer to things that are morally reprehensible or evoke strong feelings of disgust.

For example, one might describe an odious act or behavior as something that one cannot tolerate or would want to steer clear of due to its offensive nature. This aligns perfectly with the description provided in the question.

In contrast, the other terms have different meanings: "malleable" refers to the ability to be shaped or influenced, typically used in contexts involving materials or personalities; "obviate" means to prevent or remove a difficulty; and "nadir" denotes the lowest point in a situation or condition, often used in discussions of emotional states or circumstances. Thus, "odious" is the precise term that fits the description of something unpleasant that one would seek to avoid.