In Mary Shelly's Frankenstein the monster does not have a name as a way to show the he is not human. To give him a name would be to make him more human-like and there is no doubt that he is a monster.
Because the monster was never treated with kindness, never treated as a person (entity) with dignity or compassion. It had no one to name him, to tame him, to teach him. No name to respond to. No way to identify himself at all. He was self-aware but didn't have a name. Calling him "the monster" or "the demon" was degrading. It was impersonal. It was calloused. It was keeping him at more than arm's length. It was a complete and total rejection of the creation by the creator