Boundary-pushing (10)
'boundary-pushing' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for edgy that I've seen before include "Extremely" , "Uneasy" , "In a tense state" , "Apprehensive" , "Sharp in outline" .)
(Another definition for avantgarde that I've seen is " Way-out".)