It’s agony for the poor tutor again (7)
I believe the answer is:
torture
'it's agony' is the definition.
(synonyms)
'poor tutor again' is the wordplay.
'poor' indicates anagramming the letters.
'again' becomes 're' (prefix meaning 'again').
'tutor' anagrammed gives 'tortu'.
'tortu'+'re'='TORTURE'
'for the' acts as a link.
(Other definitions for torture that I've seen before include "Extreme pain" , "Inflict great suffering" , "causing pain" , "Infliction of great suffering" , "Cruel treatment" .)