- Conditioned reflex
- Conditioner
- Condolence
- Condom
- Condone
- Condor
- Conduce
- Conduction
- Conductivity
- Conducts
- Conduit
- Cone
- Confiscation
- Conflate
- Conformation
- Conformist
- Confounded
- Confrontationist
- Confused
- Confutation
- Congenital
- Congested
- Congestion
- Conniver
- Connubial
- Conquer
- Conquering
- Consecution
- Consecutive
- Consecutively
- Consent
- Consequence
- Consequent
- Conspicuous
- Constable
- Constipate
- Constipation
- Constitution
- Constitutional
- Constraint
- Constriction
- Construction
- Constructive thinking
- Consuetude
- Consul
- Consular
- Contemplation
- Contemplativeness
- Contemporaneity
- Contemporaneous
- Contemptuous
- Content
- Contest
- Contiguous
- Continent
- Continual
- Continuance
- Continuum
- Contraception
- Contractile
- Contractile vacuole
- Contraction
- Contracture
- Contradict
- Contradiction in terms
- Contraindication
- Contrariety
- Convene
- Convener , convenor
- Convent
- Convergent
- Conversational
- Conversationalist
- Converter
- Cooling
- Coolly
- Coon
- Coop
- Cooperation
- Cooperative
- Coordinated
- Coordinator
- Copacetic
- Copasetic
- Copper
- Copper coin
- Copper-coloured
- Coppice
- Copula
- Copyist
- Coral island
- Corbeille
- Cord
- Cordial
- Cordial one
- Cordless
- Cords
- Core
- Cork
- Corkage