Tried a new form of invective (6)
I believe the answer is:
tirade
'invective' is the definition.
(thesaurus)
'tried a new form of' is the wordplay.
'new form of' indicates an anagram.
'tried'+'a'='trieda'
'trieda' with letters rearranged gives 'TIRADE'.
(Other definitions for tirade that I've seen before include "A prolonged outburst of abuse" , "Flow of invective" , "A long abusive denunciation" , "A prolonged diatribe" , "Verbal onslaught" .)