Lower the reputation of revolutionary American writer (7)
I believe the answer is:
cheapen
'lower the reputation' is the definition.
'cheapen' can be an answer for 'lower' (I've seen this before). I am not certain of the 'the reputation' bit.
'revolutionary american writer' is the wordplay.
'revolutionary' becomes 'che' (Che Guevara the Marxist revolutionary).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'writer' becomes 'pen' (I've seen this before).
'che'+'a'+'pen'='CHEAPEN'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for cheapen that I've seen before include "Degrade (something)" , "Depreciate" , "Decry or devalue" , "Tried" , "decrease in value" .)