Leave extremely desirable role (6)
I believe the answer is:
depart
'leave' is the definition.
(I know that leave can be written as depart)
'extremely desirable role' is the wordplay.
'extremely' says to hollow out the word (remove centre letters) (letters on the extremes of the word are used).
'role' becomes 'part' (eg a part or role in a film).
'desirable' with its centre taken out is 'de'.
'de'+'part'='DEPART'
(Other definitions for depart that I've seen before include "Petard (anag.)" , "Go away; deviate" , "Quit" , "Make an exit" , "Set out" .)