Forthright resident reducing lead by 90 percent (5)
I believe the answer is:
vocal
'forthright' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for vocal that I've seen before include "Articulate" , "Given to speech, often in protest" , "Talkative" , "(Performance of) piece that is sung" , "Audible in protest" .)