Containing nothing; not holding or filled with anything. It can also describe a feeling of having no purpose or emotion.
From Old English *æmetiġ* meaning 'at leisure, not occupied, vacant.' Over time, the sense shifted from 'unoccupied' to 'containing nothing.' The modern spelling and sound settled in Middle English.
Originally, 'empty' was more about not being busy than not having stuff inside. So an 'empty' person was just someone not occupied, not someone hollow. Language slowly moved the word from time and activity to physical space and feelings.
Complete word intelligence in one call. Free tier — 50 lookups/day.