Removed water from river with muddy exterior (8)
I believe the answer is:
strained
'muddy exterior' is the definition.
Both the answer and definition are adjectives. Perhaps you can see a link between them that I don't see?
'removed water from river' is the wordplay.
I cannot quite see how this works, but
'water' could be 'rain' (rain is a kind of water) and 'rain' is present in the answer.
The remaining letters 'sted' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'with' acts as a link.
Can you help me to learn more?
(Other definitions for strained that I've seen before include "taut" , "Under pressure" , "taxed" , "Not relaxed; laboured" , "''The quality of mercy is not ...'' (The Merchant of Venice)" .)