Alexarchus or Alexarch was an Ancient Macedonian scholar and officer, son of Antipater and brother of Cassander. He lived around 350 to 290 BC. He is mentioned as the founder of a utopian town called Ouranopolis, in Chalcidice. Here he is said to have introduced a number of neologisms, which, though very expressive, appear to have been regarded as slang or pedantic.