The term 'Gallbladder Neighbor' refers to the organ that is located directly next to the gallbladder in the human body, which is the LIVER. The crossword solution for this term is 'LIVER', which has five letters. The LIVER is a large organ located in the upper right part of the abdomen and is responsible for many important functions in the body, such as filtering toxins from the blood, producing bile, and storing energy.