Managed to get into terrible rage in class (7)
I believe the answer is:
arrange
'class' is the definition.
(thesaurus)
'managed to get into terrible rage' is the wordplay.
'managed' becomes 'ran' (I've seen this before).
'to get into' means one lot of letters goes inside another.
'terrible' is an anagram indicator.
'rage' with letters rearranged gives 'arge'.
'ran' going into 'arge' is 'ARRANGE'.
'in' acts as a link.
(Other definitions for arrange that I've seen before include "Set in place" , "Put into a proper order" , "Put in order - organise" , "Set in order" , "Put in systematic order" .)