Exotic citrines are flawed, about ten (9)
I believe the answer is:
extrinsic
'exotic' is the definition.
(thesaurus)
'citrines are flawed about ten' is the wordplay.
'are flawed' indicates an anagram (I've seen this in other clues).
'about' is an insertion indicator.
'ten' becomes 'X' (Roman numeral).
'citrines' is an anagram of 'etrinsic'.
'etrinsic' placed around 'x' is 'EXTRINSIC'.
(Other definitions for extrinsic that I've seen before include "What's inessential" , "Foreign" , "Not essential or inherent" .)