| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 381 | Carthage | Irish | Variant of Carthach: Loving. | M | |
| 382 | Cary | Irish | Of the dark ones. | M | |
| 383 | Case | Irish | Variant of Casey: Observant; alert; vigorous. | M | |
| 384 | Casee | Irish | Brave; Vigilant. | F | |
| 385 | Casey | Irish | Brave; Vigilant. | F | |
| 386 | Casey | Irish | Observant; alert; vigorous. Famous Bearer: radio personality and voice of 'Scooby-Doo' (cartoon dog) Casey Kasem. | M | |
| 387 | Cashel | Irish | From Cashel. | M | |
| 388 | Casidhe | Irish | Clever. | F | |
| 389 | Cass | Irish | Curly-headed. | M | |
| 390 | Cassady | Irish | Variant of Cassidy: Intelligent; from Caiside; curly-headed. | M | |
| 391 | Cassian | Irish | Curly-headed. | M | |
| 392 | Cassidy | Irish | Clever; Curly-headed. | F | |
| 393 | Cassidy | Irish | Intelligent; from Caiside; curly-headed. | M | |
| 394 | Cat | Irish | Pure. | F | |
| 395 | Catelyn | Irish | Variant of Katherine meaning pure. | F | |
| 396 | Cath | Irish | Diminutive of Katherine: Pure. Clear. From the Gaelic form Caitlin. | F | |
| 397 | Cathal | Irish | Battle strong. | M | |
| 398 | Cathall | Irish | Ready for war. | M | |
| 399 | Cathaoir | Irish | Variant of Cahir: Warrior. | M | |
| 400 | Catharine | Irish | Form of the Greek Catherine meaning pure. | F | |