catalyst Antonyms

dampener anticatalyst refuter resistance retardation septum skeptic wall railing quibbler prevention preventer pessimist palisade pad obstructionist obstruction obstacle 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 objector morass membrane cynic critic crimp clog circumvallation chain breastwork breakdown blockage block barrier