A teacher upset after husband causes grief (9)
I believe the answer is:
heartache
'grief' is the definition.
(I know that grief can be written as heartache)
'a teacher upset after husband' is the wordplay.
'upset' is an anagram indicator.
'after' means one lot of letters go next to another.
'husband' becomes 'h'.
'a'+'teacher'='ateacher'
'ateacher' anagrammed gives 'eartache'.
'eartache' after 'h' is 'HEARTACHE'.
'causes' is the link.
(Other definitions for heartache that I've seen before include "Agony of Love" , "Suffering" , "mental anguish!" , "Emotional distress" , "it gives rise to anguish" .)