Time to demand a job (4)
I believe the answer is:
task
'a job' is the definition.
(I know that job can be written as task)
'time to demand' is the wordplay.
'time' becomes 't' (abbreviation).
'to demand' becomes 'ask' (synonyms).
't'+'ask'='TASK'
(Other definitions for task that I've seen before include "Errand, duty" , "Set piece of work" , "Give mission" , "exercise" , "Piece of work to be done" .)