Moved fast, gazelle? Extremely — in large open area (5)
I believe the answer is:
range
'large open area' is the definition.
(range can mean an open area of land)
'moved fast gazelle? extremely' is the wordplay.
'moved fast' becomes 'ran' (I've seen this before).
'extremely' means to remove the middle letters (only the extremes of the word are used).
'gazelle' with its centre removed is 'ge'.
'ran'+'ge'='RANGE'
'in' is the link.
(Other definitions for range that I've seen before include "Andes or Rockies, perhaps?" , "Set < compass" , "on which 'Dr Brewster Higley' felt at home?" , "Large, grassy land for livestock in the US" , "testing ground" .)