How can one best describe the act of preening?

The act of preening is best described as grooming with great care and attention. This term often refers specifically to the meticulous cleaning and arranging of feathers by birds, where they gently use their beaks to remove dirt, parasites, and to align the feathers for insulation and waterproofing. The careful nature of this behavior underscores its importance in maintaining the bird's health and appearance, highlighting the thoughtful and diligent aspect of grooming involved.

In the context of this question, other options do not accurately capture the essence of preening. Rushing through grooming implies a lack of attention, while neglecting one’s appearance suggests abandonment of grooming altogether, and wearing simple attire does not relate to grooming in any meaningful way. The focus on care and attention in preening distinctly aligns with the correct answer.