The term "caterpillar eyebrows" describes eyebrows that are thick and bushy, making them look similar to fuzzy caterpillars. This term is usually used as a personal insult or a literary description, not as a technical analysis.
Wild or fluffy eyebrows can detract from a person's beauty because they look unkempt. On the other hand, thick eyebrows can be attractive, as long as they are properly groomed. They draw attention to the eyes, shape the face and add impact to facial expressions.
To groom unruly eyebrows, simply remove the hairs that fall outside of the main eyebrow shape. These unwanted hairs can be plucked, waxed, sugared or threaded. It is best to follow the natural curve of the eyebrows; rather than changing the shape, the goal is to groom the edges. To thin especially thick brows, remove a fine line from the bottom of the brow.