Philosophical Society dons were in control (8)
I believe the answer is:
resigned
'philosophical' is the definition.
(I've seen this before)
'society dons were in control' is the wordplay.
'society' becomes 's' (common abbreviation in names of organisations).
'dons' means one lot of letters goes inside another (don means to wear or put on).
'were in control' becomes 'reigned'.
's' put inside 'reigned' is 'RESIGNED'.
(Other definitions for resigned that I've seen before include "without complaining" , "Defeatist" , "calmly accepting situation" , "Calmly submissive" , "Left work" .)