Catcher shows support for Crown (8)
I believe the answer is:
backstop
'catcher' is the definition.
(I know that catcher can be written as backstop)
'support for crown' is the wordplay.
'support' becomes 'backs' (I can't justify this - if you can you should give a lot more credence to this answer).
'for' is a charade indicator (letters next to each other).
'crown' becomes 'top' (synonyms).
'backs'+'top'='BACKSTOP'
'shows' acts as a link.
Can you help me to learn more?
(Other definitions for backstop that I've seen before include "baseball player" , "baseball catcher" .)