Mothers of Invention musician
I believe the answer is:
zappa
'mothers of invention musician' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for zappa that I've seen before include "Frank --, US guitarist and composer" , "Frank ---, US rock composer" , "Frank --, US musician" , "American musician" , "Inventive musician" .)