- Civic centre
- Civil disobedience
- Civil war
- Clash of interests
- Class conscious
- Class-war
- Classic
- Classical
- Classical antiquity
- Classified
- Clatter
- Clause
- Claustrophobic
- Clavicle
- Clearance sale
- Clearness
- Cleft lip
- Clement
- Cleromancy
- Clever feat
- Clink
- Clip
- Clippers
- Clipping
- Clitoria
- Cloakroom
- Clockwork
- Clod
- Clod hopper
- Cloister
- Clop
- Close around
- Close down
- 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
- 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
- Collective noun
- College
- Collegian
- Colliding
- Collision
- Collision course