- Contrail
- Contraption
- Convalesce
- Convection
- Conventionalist
- Conventionalize
- Conversant
- Conversely
- Convert
- Convey
- Conveyable, conveyance
- Conveyed
- Conveyor
- Convict
- Coolant
- Coolie
- Cooperate
- Coordinate
- Coot
- Cope
- Cope with
- Copilot
- Coping
- Copiously
- Cormorant
- Cornfield
- Cornstarch
- Corny
- Coronal
- Coronary
- Coroner
- Cost-effective
- Costive
- Coterie
- Cotton cloth
- Cotton plant
- Cougar
- Coughing
- Could have
- Coulomb
- Counter-revolutionary
- Counterblast
- Counterclockwise
- Counterintuitive
- Countermand
- Counterpane
- Counterpart
- Countless
- Country dance
- Country folk
- Country-boat
- County
- Covering
- Covert place
- Covertness
- Covetous
- Cow pox
- Cowardice
- Cowboy
- Cowhand
- Cowherdess
- Crag
- Crake
- Cram full
- Crammed
- Cramped
- Crams
- Crate
- Crater
- Cravat
- Craven
- Crawler
- Crawling
- Crayfish
- Crayon
- Criminality
- Criminologist
- Crinkum-crankum
- Crippling
- Crisis
- Crispy
- Criterion
- Critical
- Critical spirit
- Critical stage in small-pox
- Croak
- Crocus
- Crone
- Crony
- Croquette
- Cross
- Cross voting
- Crying
- Crypto
- Crypto communist
- Crystal
- Crystallize
- Crystals
- Csi
- Cub