Place for trial run involving you no longer (10)
I believe the answer is:
courthouse
'place for trial' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'run involving you no longer' is the wordplay.
'run' becomes 'course' (synonyms).
'involving' means one lot of letters goes inside another.
'you no longer' becomes 'thou' ('thou' historically meant 'you').
'course' placed around 'thou' is 'COURTHOUSE'.
Can you help me to learn more?
(Other definitions for courthouse that I've seen before include "suits here?" , "where the action takes place" , "government building" .)