No huge labour to make a sufficient quantity (6)
I believe the answer is:
enough
'a sufficient quantity' is the definition.
(enough means a sufficient amount)
'no huge labour' is the wordplay.
'labour' is an anagram indicator (the letters must be worked or laboured on).
'no'+'huge'='nohuge'
'nohuge' is an anagram of 'ENOUGH'.
'to make' acts as a link.
(Other definitions for enough that I've seen before include "The quantity needed, sufficient" , "Stop right now!" , "It's said to be as good as a feast" , "As much as required" , "Adequate, sufficient" .)