The term 'IMPORTANT ORGAN' can be broken down into two crossword solutions: EYE (3 letters) and LIVER (5 letters). The EYE is an important organ in the human body, responsible for vision. It is composed of several parts, including the cornea, iris, pupil, lens, and retina. The LIVER is also an important organ in the human body, responsible for many vital functions such as detoxification, protein synthesis, and production of biochemicals necessary for digestion. It is the largest internal organ in the human body and is located in the upper right side of the abdomen.