Group studying ruined remains (7)
I believe the answer is:
seminar
'group studying' is the definition.
(study group at a university)
'ruined remains' is the wordplay.
'ruined' is an anagram indicator.
'remains' with letters rearranged gives 'SEMINAR'.
(Other definitions for seminar that I've seen before include "workshop" , "Group discussion of subject" , "Academic class" , "Meeting for study" , "Working meeting in College" .)