Catty remark about a duke in field (6)
I believe the answer is:
meadow
'field' is the definition.
(a meadow is a field)
'catty remark about a duke' is the wordplay.
'catty remark' becomes 'meow' (I've seen this in another clue).
'about' indicates putting letters inside.
'duke' becomes 'd' (abbreviation).
'a'+'d'='ad'
'meow' enclosing 'ad' is 'MEADOW'.
'in' is the link.
(Other definitions for meadow that I've seen before include "Seventeen dn used for hay" , "Low-lying grassland" , "Pasture" , "Area used for hay" , "A field of lush grass" .)