- Cleanliness
- Cleanness
- Cleverness
- Cliff
- Climbers
- Climbing plant
- Climbing stem
- Clinging
- Clinging steadfastedly on
- Clinical psychology
- Close with
- Close-knit
- Closeted
- Closing
- Closing the eyes
- Closure
- Clothes
- Clothesline
- Clothing
- Cloud nine
- Clouds
- Clove
- Cloven
- Clownish
- Cloze test
- Club
- Cluck
- Clueless
- Clumsily
- Clumsy
- Clunker
- Clutter
- Coals
- Coals to new castle
- Coast
- Coat of arms
- Coated
- Coattails effect
- Cobalt bomb
- Cobble
- Cobbler
- Cobol
- Cobra
- Cocaine
- Cock
- Codex
- Codger
- Coed
- Coefficient
- Coessential
- Coffee break
- Coffee plant
- Coffer
- Cogitate
- Cogitation
- Cogitative
- Cognate
- Cognisance
- Cold storage
- Cold war
- Cold-blooded
- Cold-hearted
- Coleslaw
- Coliform
- Coliseum
- Colitis
- Collaboratively
- Collage
- Collapse
- Collapsible
- Collar beam
- Collectedly
- Colon
- Colonial
- Colonialism
- Colonization
- Colonize
- Colophon
- Colophony
- Colorectal
- Colour bar
- Colour printing
- Colouring
- Colt
- Come into ones own
- Come out
- Come through
- Come to grief
- Come to his senses
- Commingle
- Come to the surface
- Come together
- Come under
- Comely
- Comemorated
- Comet
- Comfort station
- Comical
- Comilona
- Commissary