Someone who makes robots. Derived from the German "roboter", meaning robot. Removing the "r" and the "o", you get boter. Hence "Boterman"

This word was first coined by world renowned literary genius Dicky Scricca in 2008. He first thought of it when he saw someone selling robots. One of the was named "Robotman", and he took the German term he was already familiar with (roboter) and people just rolled with it.