An accumulation of jobs not done (7)
I believe the answer is:
backlog
'an accumulation of jobs not done' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for backlog that I've seen before include "Accumulation (of work) to be dealt with" , "Work yet to be done" , "Work piled up" , "Arrear of wooden kind?" , "Go black with arrears of work" .)