Forthright victory on coal production (5)
I believe the answer is:
vocal
'forthright' is the definition.
(I've seen this before)
'victory on coal production' is the wordplay.
'victory' becomes 'v' ().
'on' indicates putting letters inside.
'production' indicates an anagram.
'coal' is an anagram of 'ocal'.
'v' placed into 'ocal' is 'VOCAL'.
(Other definitions for vocal that I've seen before include "speaking loudly" , "To do with the voice, say cords" , "Relating to the human voice" , "Articulate" , "For, giving, voice" .)