Sin, syn, cin

Satan In, INS, Innes, insurance, and sinterklaas

Breaking God's Law (and Bigelow tea!):  Sincere, sinecure, sinusitis, Sinead o'connor, singing, sink, Sinn Fein, Singapore, Sindh province, Sinai, Sinaloa, Sinbad, raisins, sinciput, sine qua non, sinew, singed, Sinhalese, single, sinsemilla, sinter, Sinology

syn- (acting together), synagogue, syntax, synesthesia, synthetic, synonym,  synapse, synastry, synchronization, syncopation, syncretism, syndication, synectics, synergy, synopsis, synthesizer, syndicalist, syntonic

cinema, incinerator, cinch, Cinderella, Cincinnati, cinnamon, carcinogen

ensign