Container of schoolbooks the class endlessly rearranged (7)
I believe the answer is:
satchel
'container of schoolbooks' is the definition.
(satchels often contain schoolbooks)
'the class endlessly rearranged' is the wordplay.
'endlessly' means to remove the last letter.
'rearranged' is an anagram indicator.
'the'+'class'='theclass'
'theclass' with its last letter taken off is 'theclas'.
'theclas' with letters rearranged gives 'SATCHEL'.
(Other definitions for satchel that I've seen before include "Schoolbag found in chalets" , "Text mark for an insertion" , "Bag with a strap for books" , "Schoolbag for children's books" , "Bag for school books" .)