- Cloister
- Clop
- Close around
- Close down
- Clouds
- Clove
- Cloven
- Clownish
- Cloze test
- Club
- Cluck
- Clueless
- Clumsily
- Clumsy
- Clunker
- Clutter
- 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
- Collective noun
- College
- Collegian
- Colliding
- Collision
- Collision course
- Collusiveness
- Collyrium
- Colocasia
- 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
- Commercial
- Commiseration
- Common sense
- Communalism
- Communicable
- Communication
- Communication satellite
- Comorbid
- Compiling
- Complacence
- Complete eradication