Cession vs. Session
Choose vs. Chose
Circumnavigate vs. Circumvent
Site vs. Cite
Classical vs. Classic
Cleanness vs. Cleanliness
Clench vs. Clinch
Click vs. Clique
Climactic vs. Climatic
Clime vs. Climb
Close vs. Clothes
Coarse vs. Course
Collaborate vs. Cooperate
Compact vs. Contract
Comparable vs. Comparative
Complement vs. Compliment
Complementary vs. Complimentary
Completion vs. Completeness
Comportment vs. Deportment
Compose vs. Comprise