Content to name a downland field (6)
I believe the answer is:
meadow
'field' is the definition.
(a meadow is a field)
'content to name a downland' is the wordplay.
'content to' indicates the answer is hidden within the clue.
'MEADOW' can be found hidden inside 'name a downland'.
(Other definitions for meadow that I've seen before include "somewhere grassy" , "area of grassland" , "A field of rich grass" , "Piece of grassland" , "In rural location" .)