Avoiding waste (6)
I believe the answer is:
frugal
'avoiding waste' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for frugal that I've seen before include "Taking care" , "Thrifty or parsimonious" , "not extravagant" , "Economical, avoiding waste" , "Sparing, meagre" .)