Sweet time not working middle of week (6)
I believe the answer is:
toffee
'sweet' is the definition.
(toffee is a kind of sweet)
'time not working middle of week' is the wordplay.
'time' becomes 't' (abbreviation).
'not working' becomes 'off' (switched off).
'middle of' means to look at the middle letters.
The middle letters of 'week' are 'ee'.
't'+'off'+'ee'='TOFFEE'
(Other definitions for toffee that I've seen before include "can we not do something for it?" , "Type of sweet" , "Chewy stuff" , "Chewy confectionery" , "Chewy confection" .)