Murphy, perhaps, reformed the brute! (5)
I believe the answer is:
tuber
'murphy' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'reformed the brute' is the wordplay.
'reformed' indicates an anagram.
'brute' is an anagram of 'TUBER'.
'perhaps' acts as a link.
Can you help me to learn more?
(Other definitions for tuber that I've seen before include "traveller down in London?" , "Thickened fleshy root" , "Fleshy root, vegetable say" , "Fleshy underground part of a stem, often used as food" , "Root eg of potato" .)