Irksome Edward promises to pay (7)
I believe the answer is:
tedious
'irksome' is the definition.
('tedious' can be a synonym of 'irksome')
'edward promises to pay' is the wordplay.
'edward' becomes 'ted'.
'promises to pay' becomes 'ious' (more than one iou).
'ted'+'ious'='TEDIOUS'
(Other definitions for tedious that I've seen before include "not exciting" , "flat" , "Dull as ditchwater" , "Boring, monotonous" , "Long, slow, dull" .)