Monster around river, not quite so alone (10)
I believe the answer is:
friendless
'alone' is the definition.
(I've seen this before)
'monster around river not quite' is the wordplay.
I cannot really understand how this works, but
'river' could be 'r' (abbreviation for river) and 'r' is found in the answer.
'monster' could be 'fiend' (synonyms) and 'fiend' is present in the leftover letters.
'not' could be 'less' (I've seen this in other clues) and 'less' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'so' is the link.
Can you help me to learn more?
(Other definitions for friendless that I've seen before include "Lacking pals" , "such as Billy-No- Mates" , "Socially isolated" , "one unable to be with mates" , "lonely" .)