No idle presence within Airedale region (4)
I believe the answer is:
area
'region' is the definition.
(synonyms)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for area that I've seen before include "environs" , "Region; extent of a surface" , "Field of activity or surface" , "field of study" , "District; locale" .)