Poet's son unfriendly towards Ezra oddly (8)
I believe the answer is:
schiller
'poet's' is the definition.
(I have seen 'German poet' mean 'schiller' so perhaps 'poet' could also mean 'schiller')
'son unfriendly towards ezra oddly' is the wordplay.
'son' becomes 's'.
'unfriendly' becomes 'chill'.
'towards' means one lot of letters go next to another (I've seen this in other clues).
'oddly' indicates alternate letters.
The alternating letters of 'ezra' are 'er'.
's'+'chill'+'er'='SCHILLER'
(Other definitions for schiller that I've seen before include "German dramatist/poet" , "German poet and playwright" , "German author" , "German poet, dramatist; William Tell, Maria Stuart" , "German writer" .)