Charming area within reach across river (8)
I believe the answer is:
adorable
'charming' is the definition.
(I've seen this in another clue)
'area within reach across river' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'within reach' becomes 'doable' (I've seen this in another clue).
'across' indicates putting letters inside.
'river' becomes 'r' (abbreviation for river).
'doable' enclosing 'r' is 'dorable'.
'a'+'dorable'='ADORABLE'
(Other definitions for adorable that I've seen before include "winning" , "Very pleasing" , "worthy of love" , "Attractive - captivating" , "Winsome" .)