Tiresome editor promises to pay after time (7)
I believe the answer is:
tedious
'tiresome' is the definition.
('tedious' can be a synonym of 'tiresome')
'editor promises to pay after time' is the wordplay.
'editor' becomes 'ed'.
'promises to pay' becomes 'ious' (more than one iou).
'after' is a charade indicator (letters next to each other).
'time' becomes 't'.
'ed'+'ious'='edious'
'edious' after 't' is 'TEDIOUS'.
(Other definitions for tedious that I've seen before include "not worth listening to?" , "Banal" , "awfully boring" , "flat" , "not exciting" .)