Tunnel builder is a job that involves the construction of tunnels, often for transportation or utility purposes. The term can refer to two different types of workers: an ANT (3 letters) and an EMMET (5 letters). An ANT is a type of insect that is known for its ability to dig tunnels in the ground. An EMMET is a type of worker who specializes in the construction of tunnels, often using heavy machinery. Both ants and emmets are essential to the successful completion of tunnel building projects.