Area within field sport that's evocative (8)
I believe the answer is:
haunting
'evocative' is the definition.
(I've seen this before)
'area within field sport' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'within' is an insertion indicator.
'field sport' becomes 'hunting' (I've seen this before).
'a' inserted within 'hunting' is 'HAUNTING'.
'that's' acts as a link.
(Other definitions for haunting that I've seen before include "pursuit of ghosts" , "Lingering in the mind, like ghost" , "Willing to take chances" , "Frequenting a place, as a ghost might" , "Ghost visitation on ninth Aug" .)