Assert, Contend, Maintain
When saying that someone is presenting a claim/belief/position
Beseech, Implore, Entreat, Exhort
When saying that someone works to persuade an audience to follow a course of action
Galvanize, Impel
When saying that someone inspires/excites/rouses that audience
Cogent, Coherent
When describing someone’s argument as convincing/persuasive
Imprudent, Myopic
When saying that someone’s idea/plan/argument is flawed or ill-conceived
Facile, Glib
When saying that an argument/position is oversimplified or superficial
Decry, Inveigh (against), Rebuke
When saying that someone condemns or criticizes something/someone
Diatribe, Harangue
When you want a noun for an extended or impassioned attack/rant
Calamitous, Ruinous
When saying that a course of action has been (or would be) disastrous
Elucidate
When you want another word for “explain”
Obfuscate
When you want a word that does the opposite
Salient
When you want a word to describe a key/important point