Make out traces in a design (9)
I believe the answer is:
ascertain
'make out' is the definition.
(thesaurus)
'traces in a design' is the wordplay.
'design' indicates anagramming the letters.
'traces'+'in'+'a'='tracesina'
'tracesina' with letters rearranged gives 'ASCERTAIN'.
(Other definitions for ascertain that I've seen before include "settle" , "Prove" , "Establish (the facts)" , "Get to know" , "Become aware" .)