Playwright avoids island during wonderful leave (7)
I believe the answer is:
absence
'leave' is the definition.
(thesaurus)
'playwright avoids island during wonderful' is the wordplay.
'playwright' becomes 'ibsen' (Henrik Ibsen, 1828-1906).
'avoids' is a deletion indicator.
'island' becomes 'i' (geographical abbreviation).
'during' means one lot of letters goes inside another.
'wonderful' becomes 'ace' (ace can informally mean very good).
'ibsen' with 'i' taken out is 'bsen'.
'bsen' going into 'ace' is 'ABSENCE'.
(Other definitions for absence that I've seen before include "Need" , "It's said to make the heart grow fonder" , "reason for better relationship?" , "form of inattention?" , "It may make the heart grow fonder" .)