Poor-quality wood used in test (6)
I believe the answer is:
trashy
'poor' is the definition.
(thesaurus)
'quality wood used in test' is the wordplay.
'quality wood' becomes 'ash' (wood from an ash tree. I am not sure about the 'quality' bit.).
'used in' indicates putting letters inside.
'test' becomes 'try' (synonyms).
'ash' going into 'try' is 'TRASHY'.
Can you help me to learn more?
(Other definitions for trashy that I've seen before include "Cheap - garish" , "As rubbish" , "Cheap, shoddy" , "Poorly made" , "Of poor quality" .)