Knight escapes from a Welsh town diminished (8)
I believe the answer is:
abridged
'diminished' is the definition.
Both the answer and definition are adjectives. Maybe you can see a link between them that I don't see?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for abridged that I've seen before include "Epitomised" , "Abbreviated, contracted" , "Cut short - big adder (anag)" , "Shortened as book may be" , "Shorter" .)