Proverbial madman on tail of nervous wreck (7)
I believe the answer is:
shatter
'nervous wreck' is the definition.
'shatter' can be an answer for 'wreck' (I've seen this before). I am not sure about the 'nervous' bit.
'proverbial madman on tail of' is the wordplay.
'proverbial' becomes 's' (I am not sure about this - if you are sure you should believe this answer much more).
'madman' becomes 'hatter' (mad as a hatter).
'on tail of' means one lot of letters go next to another (to be on the tail of someone is to follow them).
's'+'hatter'='SHATTER'
Can you help me to learn more?
(Other definitions for shatter that I've seen before include "Threats (anag.)" , "Completely upset" , "Break into fragments" , "Go to pieces" , "Crack" .)