Waller took top tip from Roach -- piano's inside (7)
I believe the answer is:
hadrian
'waller' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's an association between them I don't understand?
'took top tip from roach piano's inside' is the wordplay.
'took top' becomes 'had' (I can't explain this - if you can you should believe this answer much more).
'tip from' says to take the initial letters.
'inside' means to look at the middle letters.
The middle of 'piano' is 'ian'.
The initial letter of 'roach' is 'r'.
'had'+'r'+'ian'='HADRIAN'
Can you help me to learn more?
(Other definitions for hadrian that I've seen before include "Wall-building Roman emperor" , "Roman emperor who built the British wall" , "Roman emperor who visited Britain" , "Imperial wall-builder" , "Roman emperor and wallbuilder" .)