Will have a ten a.m. break after the exam (9)
I believe the answer is:
testament
'will' is the definition.
(synonyms)
'a ten a m break after the exam' is the wordplay.
'break' indicates an anagram.
'after' means one lot of letters go next to another.
'the exam' becomes 'test' ('test' can be a synonym of 'exam').
'ten'+'m'='tenm'
'tenm' with letters rearranged gives 'ment'.
'a'+'ment'='ament'
'ament' put after 'test' is 'TESTAMENT'.
'have' acts as a link.
(Other definitions for testament that I've seen before include "New and old parts of the Bible" , "evidence" , "it could be old or new" , "Will - part of bible" , "Will or solemn declaration" .)