Eliminating waste when absorbing direction, a quality stars have (9)
I believe the answer is:
twinkling
'a quality stars have' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'eliminating waste when absorbing direction' is the wordplay.
'eliminating waste when' becomes 'tinkling' (I can't explain this - if you can you should give a lot more credence to this answer).
'absorbing' indicates putting letters inside.
'direction' becomes 'w' (W is an example).
'tinkling' enclosing 'w' is 'TWINKLING'.
Can you help me to learn more?
(Other definitions for twinkling that I've seen before include "Second" , "How stars appear" , "Shining intermittently" , "Sparkling - moment" , "Instant" .)