Evil area in Bastille (3)
I believe the answer is:
ill
'evil' is the definition.
(I've seen this in other clues)
'area in bastille' is the wordplay.
'area' says the answer is hidden in the clue (I've seen 'area of' mean this (I've seen this in other clues)).
'ILL' is hidden within 'in bastille'.
(Other definitions for ill that I've seen before include "Sickly" , "Under the weather" , "Infirm" , "Faulty" , "Out of sorts" .)