Buttonholed by Edward, relation teased (7)
I believe the answer is:
taunted
'teased' is the definition.
('taunt' can be a synonym of 'tease')
'buttonholed by edward relation' is the wordplay.
'buttonholed by' means one lot of letters goes inside another (buttonhole can mean to detain or hold).
'edward' becomes 'ted'.
'relation' becomes 'aunt' (aunt is a kind of relation).
'ted' enclosing 'aunt' is 'TAUNTED'.
(Other definitions for taunted that I've seen before include "Deliberately provoked by poking fun at" , "Mocked, jeered" , "Derided, mocked" , "Jeered at in a cruel and hurtful way" , "Twitted" .)