To slip badly in a Shakespearean role (6)
I believe the answer is:
pistol
'a shakespearean role' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'to slip badly in' is the wordplay.
'badly' indicates an anagram (letters in the wrong order).
'in' indicates putting letters inside.
'slip' with letters rearranged gives 'pisl'.
'to' put into 'pisl' is 'PISTOL'.
Can you help me to learn more?
(Other definitions for pistol that I've seen before include "pop" , "Hand weapon" , "Spoilt these guns" , "Piece" , "Rectangular" .)