To return a greeting in a Shakespearean play (7)
I believe the answer is:
othello
'a shakespearean play' is the definition.
(I've seen this before)
'to return a greeting' is the wordplay.
'return' shows that the letters should be reversed in order.
'a greeting' becomes 'hello' (hello is a kind of greeting).
'to' back-to-front is 'ot'.
'ot'+'hello'='OTHELLO'
'in' is the link.
(Other definitions for othello that I've seen before include "Eponymous hero" , "player from Stratford" , "Shakespearean play" , "Shakespeare's tragic Moor who killed his wife" , "Literary character" .)