Exclude Delta poet (4)
I believe the answer is:
bard
'poet' is the definition.
(I've seen this before)
'exclude delta' is the wordplay.
'exclude' becomes 'bar' ('bar' can be a synonym of 'exclude'**).
'delta' becomes 'd' (phonetic alphabet: alpha, bravo, charlie etc.).
'bar'+'d'='BARD'
(Other definitions for bard that I've seen before include "Poet; sounds like forbidden" , "Celtic poet" , "Animal; cruel person" , "A drab sort of old poet" , "Traditional poet" .)