Most within reach are in retreat (7)
I believe the answer is:
nearest
'most within reach are in retreat' is the definition.
I can't judge whether this definition defines the answer.
'most within reach are in retreat' is the wordplay.
'most' means to remove the first letter.
'within reach' becomes 'near' (I've seen this before).
'are in' indicates putting letters inside.
'retreat' becomes 'nest' (nest is a kind of retreat).
'near' with its first letter taken off is 'ear'.
'ear' placed inside 'nest' is 'NEAREST'.
Can you help me to learn more?
(Other definitions for nearest that I've seen before include "Closest among relatives" , "Close family members" , "Most intimate" , "Next" , "Closest, being earnest" .)