"Juno and the Paycock” playwright Sean (6)
I believe the answer is:
ocasey
(Other definitions for ocasey that I've seen before include "Sean . . . . . . wrote ''The Plough and the Stars'' (1 '5)" , "Sean . . . . . ., great Irish playwright of 'The Plough and the Stars' (1'5)" , "Sean ..., author of 'The Plough and the Stars'" , "Sean .' ....., author of ` `The Silver Tassie' ' (1'5)" , "Sean . . . . . . wrote 'Juno and the Paycock'" .)