There are several synonyms for the word "harnesser", which is a noun that refers to someone who puts a harness on an animal or who harnesses a tool or resource for a particular purpose. Other words that can be used in place of "harnesser" include "user", "exploiter", "controller", "manager", "harvester", "operator", "utilizer", "manipulator", "coordinator", and "director". These synonyms all convey the idea of someone who takes control of something and uses it to achieve a specific goal. Whether it's a person harnessing the potential of a new technology or a trainer harnessing the power of a horse, the skills of a harnesser can be invaluable.