Acephali simply means “headless” or “without head” in Ancient Greek (from Ancient Greek: ἀκέφαλοι “headless”, singular ἀκέφαλος akephalos from ἀ- a-, “without”, and κεφαλή kephalé, “head”). And as such, if you look up the creature Acephali, you may find it hard to get much information, because Acephali became a term – often used in the Church – for sects or religions without a “head” or leader. I can imagine this being quite the put-down in its day.
The Acephali as an imaginary creature is usually depicted simply as a human with no head and a face on their torso instead – a guy has got to eat right?
Fabled human-like creatures in Greek mythology, similar to Pliny the Elder’s Blemmyae.