1670s, "philosophy or doctrines of the Cynics" (indifference to pleasure, stoicism pushed to austerity, asceticism), from cynic + -ism. Meaning "cynical character" is from 1847. For nuances of usage, see humor (n.).
cymbal
Cymric
cynanthropy
cynic
cynical
cynicism
cynocephalic
cynosure
Cynthia
cypress
Cyprian