The term 'Hill Builder' can be broken down into two crossword solutions: ANT (3 letters) and EMMET (5 letters). Ants are small, social insects that live in colonies and are known for their ability to build hills of dirt and sand. An EMMET is a type of ANT, specifically a worker ANT, which is responsible for the construction of the hill. Worker ants are the most common type of ANT and are responsible for the majority of the hill building.