Great poet's school gets worse (8)
I believe the answer is:
schiller
'great poet's' is the definition.
'school gets worse' is the wordplay.
'school' becomes 'sch'.
'gets' says to put letters next to each other.
'worse' becomes 'iller'.
'sch'+'iller'='SCHILLER'
(Other definitions for schiller that I've seen before include "Author of Ode to Joy" , "German writer" , "German poet and playwright" , "German dramatist/poet" , "German poet, dramatist; William Tell, Maria Stuart" .)