Infundibular refers to a funnel-shaped opening or passage in the body. Antonyms for this word could include terms such as flat, straight, narrow, or closed, which represent the opposite characteristics of an infundibular structure. Flat and straight suggest a lack of curvature or narrowing, while narrow signifies a small, confined opening. Closed indicates that there is no opening at all. These words can be used to describe structures or organs that are different from those with an infundibular design, such as the nasal passages or skin pores. By using antonyms, we can better describe and differentiate between various anatomical features.