In pop culture and modern fiction it’s used to mean an artificial human – e.g. see the examples in https://en.wikipedia.org/wiki/Homunculus#In_popular_culture like Fullmetal Alchemist for an idea of what OP was going for. (In this case, more Frankenstein’s monster though.)

There is also the “little man who makes things work” idea like a golem – which is related, but not the sense used here.