Scientist, absent-minded, departs for West (7)
I believe the answer is:
faraday
'scientist' is the definition.
(Michael Faraday)
I don't understand the rest of the clue.
(Other definitions for faraday that I've seen before include "Scientist" , "Man of note" , "Michael -, nineteenth century English physicist and chemist" , "English physicist and chemist, d. 1867" , "unit" .)