Rosencrantz and Guildenstern initially tease (3)
I believe the answer is:
rag
'tease' is the definition.
('rag' can be a synonym of 'tease')
'rosencrantz and guildenstern initially' is the wordplay.
'initially' suggests taking the first letters.
The initial letters of 'rosencrantz and guildenstern' is 'RAG'.
(Other definitions for rag that I've seen before include "Cheap newspaper" , "Sensational paper" , "jazz number" , "organ?" , "Small piece of cloth and university week" .)