- 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
- Cockalarum
- Cockscomb
- Cocksure
- Cocktail
- Coco
- Coconut
- Cocopeat
- Coddle
- Code
- Cognoscente
- Cohabitation
- Cohesively
- Cohort
- Coil
- Coin
- Coin money
- Coiner
- Col
- Cold cuts
- 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
- Collusiveness
- Collyrium
- Colocasia
- Comb
- Combative
- Combing
- Come
- Come across
- Come and go
- Come at