I test duet out - it's poor (9)
I believe the answer is:
destitute
'poor' is the definition.
(similar in meaning)
'i test duet out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'i'+'test'+'duet'='itestduet'
'itestduet' is an anagram of 'DESTITUTE'.
'it's' acts as a link.
(Other definitions for destitute that I've seen before include "In utter want" , "Impoverished, indigent" , "Absolutely broke, without money or goods" , "Poverty-stricken" , "Without money or resources" .)