decease n. + Add to list US //dɪˈsis// UK //dɪsˈiːs// de·cease Archaic Formal SynonymsAntonymsEtymology Synonyms deathdieexitexpireexpirygopassperish Antonyms birthOriginLATdēcessus→OFRdeces→ENdecease From Old French deces (Modern French décès), from Latin dēcessus (“departure”).