Manufactured chest with tiny adjustment (9)
I believe the answer is:
synthetic
'manufactured' is the definition.
(thesaurus)
'chest with tiny adjustment' is the wordplay.
'with' says to put letters next to each other.
'adjustment' indicates an anagram (the order of letters is adjusted).
'chest'+'tiny'='chesttiny'
'chesttiny' is an anagram of 'SYNTHETIC'.
(Other definitions for synthetic that I've seen before include "ersatz" , "Artificial, man-made compound" , "Manufactured, not produced naturally - say material" , "substance" , "Fake" .)