Arrears of work (7)
I believe the answer is:
backlog
'arrears of work' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for backlog that I've seen before include "pile needing attention?" , "Arrear of wooden kind?" , "Build-up of work still to be dealt with" , "Accumulation (of work) to be dealt with" , "Go black with arrears of work" .)