Don't start contract for lack of labour (4)
I believe the answer is:
ease
'lack of labour' is the definition.
'ease' can be an answer for 'lack' (I have seen 'Lack of difficulty ' mean 'ease' so perhaps 'lack' could also mean 'ease'). I'm not sure about the 'of labour' bit.
'don't start contract' is the wordplay.
'don't start' means to remove the first letter.
'contract' becomes 'lease' (leasing is a kind of contracting).
'lease' with its initial letter taken away is 'EASE'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for ease that I've seen before include "Make less hard" , "Assuage" , "Affluence" , "Make comfortable" , "Allay" .)