Cyseinio, v. to sound together
Cysellt, n. an opportunity
Cysgfa, n. numbness
Cysgiad, n. a sleeping
Cysgiadol, a. soporific, soniferous
Cysgiadur, n. a sleeper; a sluggard; a dormant animal
Cysgiadyr, n. an opiate
Cysglyd, a. sleepy, drowsy
Cysgod, n. a shadow, a shade; a shelter
Cysgodfa, n. a shady place