Unknown wild area to the north offering lots of space (5)
I believe the answer is:
roomy
'offering lots of space' is the definition.
(roomy means spacious)
'unknown wild area to the north' is the wordplay.
'unknown' becomes 'y' (algebra).
'wild area' becomes 'moor'.
'to the north' says the letters should be written backwards (in a down clue, letters go up or 'northward').
'y'+'moor'='ymoor'
'ymoor' written backwards gives 'ROOMY'.
(Other definitions for roomy that I've seen before include "Voluminous" , "Having plenty of space" , "Without cramping" , "Capacious" , "so wide" .)