catalyst Antonyms

dampener anticatalyst anabolyst railing refuter resistance retardation septum skeptic quibbler prevention preventer pessimist palisade pad obstructionist obstruction obstacle objector wall encirclement let in spent catalyst dead-catalyst blind fools of fate disincentive naysaying naysayer infarct let go of plosive faultfinder killjoy roadblock handrail let down blocking agent blocker morass misanthrope membrane cynic critic crimp clog circumvallation chain breastwork breakdown blockage