Sentence:  [Pages 114–115] [H]e [Aristotle] tells us expressly, that that which we call the rational soul is ... 'separable from the body,' ... 'because it is not the <WSD>entelech</WSD> of any body.' ... &#91;[https://books.google.com/books?id=ky4NAAAAYAAJ&pg=PA500 page 500]&#93; Wickedness is the form and <WSD>entelech</WSD> of all the wicked spirits: it is the difference of a name, rather than any proper difference of natures that is between the devil and wicked men. 
Meaning of the word marked with <WSD> tags:  The complete realisation and final form of some potential concept or function; the conditions under which a potential thing becomes actualized.