Duck and orange ordered for herb (7)
I believe the answer is:
oregano
'herb' is the definition.
(oregano is a kind of herb)
'duck and orange ordered' is the wordplay.
'duck' becomes 'o'.
'and' means one lot of letters go next to another.
'ordered' is an anagram indicator.
'orange' is an anagram of 'regano'.
'o'+'regano'='OREGANO'
'for' is the link.
(Other definitions for oregano that I've seen before include "part of Mediterranean diet?" , "Mediterranean herb" , "Sweet-smelling herb" , "aromatic plant" , "that's aromatic" .)