Judges thus arresting conservative thinker (8)
I believe the answer is:
socrates
'thinker' is the definition.
(I have seen 'Deep thinker' mean 'socrates' so perhaps 'thinker' could also mean 'socrates')
'judges thus arresting conservative' is the wordplay.
I cannot really see how this works, but
'judges' could be 'rates' (rating is a kind of judging) and 'rates' is found within the answer.
'thus' could be 'so' (synonyms) and 'so' is found in the answer.
'conservative' could be 'c' (UK political abbreviation) and 'c' is present in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for socrates that I've seen before include "Coarsest (anag) - philosopher" , "2 [PHILOSOPHER]" , "Philosophical Greek" , "Man philosophically questioning" , "Deep thinker" .)