"Hamilton” role (4)
I believe the answer is:
burr
'hamilton role' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for burr that I've seen before include "Rotary file - feature of some regional accents" , "trouble" , "Prickly, clinging seed-case" , "Former US vice-president - dialect way of pronouncing R" , "Whirring sound; form rough edge on (metal)" .)