Aristotle finally caught in this moral framework (6)
I believe the answer is:
ethics
'moral framework' is the definition.
(ethical or moral system)
'aristotle finally caught in this' is the wordplay.
'finally' indicates one should take the final letters.
'caught' becomes 'c' (cricket abbreviation).
'in' is an insertion indicator.
The final letter of 'aristotle' is 'e'.
'c' placed inside 'this' is 'thics'.
'e'+'thics'='ETHICS'
(Other definitions for ethics that I've seen before include "Science of morals" , "Philosophical study of moral values" , "High standards" , "Professional codes of behaviour.18 Serious or heartfelt" , "Some philosophy" .)