| Cintugnatus | Conqueror of the Tuatha Dé Danann, a title given to a Celtic leader |
| Cintusmus | Conqueror of the Tuscan people, a title given to a Celtic leader |
| Cinuchan | Battle-hardened warrior, a Celtic name meaning strong in battle |
| Cinuedu | Battle-lover, a Celtic name meaning fond of war |
| Cinuin | Battle-hardened warrior, a Celtic name meaning strong in battle |
| Cinuoc | Battle-lover, a Celtic name meaning fond of war |
| Ciolla | Battle-hardened warrior, a Celtic name meaning strong in battle |
| Ciorra | Battle-lover, a Celtic name meaning fond of war |
| Cipio | To seize, a Latin name meaning to take or capture |
| Cippa | To seize, a Latin name meaning to take or capture |
| Ciriacus | Belonging to Ciriacus, a Latin name referring to a specific person |
| Cistumucus | Possibly derived from Latin, meaning 'of the chest' or 'breast' |
| Citoc | Possibly derived from Greek, meaning 'of the city' or 'citizen' |
| Ciuarheru | Possibly derived from Latin, meaning 'of the spear' or 'spearman' |
| Clac | Possibly derived from Latin, meaning 'clear' or 'bright' |
| Clacc | Possibly derived from Latin, meaning 'of the lake' or 'lake dweller' |
| Clack | Chatterer; Large Man |
| Claellus | Possibly derived from Latin, meaning 'of the shore' or 'shore dweller' |
| Clarembald | Derived from Old French, meaning 'bright shield' or 'shining protector' |
| Clariance | Derived from Old French, meaning 'bright shield' or 'shining protector' |
| Clarions | Derived from Old French, meaning 'clear voice' or 'loud trumpet' |
| Claudin | Derived from Latin, meaning 'lame' or 'crippled' |
| Clauds | Derived from Latin, meaning 'lame' or 'crippled' |
| Clavance | Derived from Old French, meaning 'of the key' or 'key holder' |
| Clavin | Derived from the Latin for bald. |
| Clen | Possibly derived from Old English, meaning 'narrow' or 'slender' |
| Clessy | Possibly derived from Old English, meaning 'clever' or 'skilled' |
| Cleton | Possibly derived from Old English, meaning 'clever' or 'skilled' |
| Clevan | A variant of the name Cleve. |
| Cleven | One who lives near a cliff. |
| Clochides | Derived from Greek, meaning 'of the cloak' or 'cloak wearer' |
| Clodwal | Derived from Old English, meaning 'famous ruler' or 'renowned leader' |
| Clotuali | Derived from Old English, meaning 'famous ruler' or 'renowned leader' |
| Clutarigas | Derived from Old English, meaning 'famous warrior' or 'renowned fighter' |
| Clvtori | Possibly derived from Latin, meaning 'of the forest' or 'forest dweller' |
| Clvtorigi | Derived from Old English, possibly meaning 'clever origin' or 'clever birth' |
| Clyton | Clay Settlement |
| Cnapa | Old English name, possibly meaning 'battle' or 'warrior' |
| Cnebba | Old English name, possibly meaning 'bright' or 'shining' |
| Cobie | Diminutive form of Robert, meaning 'bright fame' |