- Clam up
- Clammy
- Clamor
- Clamour
- Clamp down on
- Clap of thunder
- Clay
- Clean down
- Clean from
- Clean hands
- Clean-handed
- Clean-shaven
- 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
- Cmos
- Co-education
- Co-heir
- Co-opt
- Co-respondent
- Co-star
- Co-worker
- Coach
- Coach load
- Coagulate
- Coalgate
- Cockalarum
- Cockscomb
- Cocksure
- Cocktail
- Coco
- Coconut
- Cocopeat
- Coddle
- Code
- 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
- Coming to blows
- Comma bacillus
- Command-ed
- Commander-in-chief
- Commandments
- Commando
- Commandos
- Comme il faut
- Commemorate
- Commemoration
- Commence
- Commendable
- Commensurable
- Commensurable ness
- Commentary
- Commentate, commentator