A character seen on autumn break (4,5)
I believe the answer is:
fall apart
'break' is the definition.
(I know that break can be written as fall apart)
'a character seen on autumn' is the wordplay.
'character' becomes 'part' (a part in a play).
'seen on' means one lot of letters go next to another.
'autumn' becomes 'fall' (synonyms).
'a'+'part'='apart'
'apart' after 'fall' is 'FALL APART'.
(Other definitions for fall apart that I've seen before include "Disintegrate" , "Come to pieces" , "Go to pieces" .)