The words in the following list represent misunderstanding of the words’ meanings and not simply an inability to spell them correctly. This post covers words starting with the letters c and d (the a-b list is here).
1. canvas / canvass
The OED and M-W both show the spelling canvas as a variant spelling of the verb ”to canvass,” but Chicago, AP, and Paul Brians (Common Errors in English Usage) all agree that the verb meaning “to survey” is spelled with a double s. The spelling canvas is a noun signifying a heavy cloth.
2. clench / clinch
Although both words share their origin, in modern usage they are not interchangeable. You clench your fist or teeth, but clinch a deal or a victory. In boxing, “to clinch” means “to grapple at close quarters.” As a noun,clinch is used colloquially to mean “an embrace.”
3. compliment / complement
Both words may be used as either nouns or verbs. A compliment is a praising remark; a complement is something that enhances or completes. “To compliment” is to praise”; “to complement” is “to complete.”
4. conscience / conscious
Conscience is a noun that refers to the sense of right and wrong in an individual. Conscious is an adjective that means “aware of.”
5. corporal / corporeal
Both words are adjectives that mean “of the body,” but in modern usage corporeal is used in philosophical or theological discussions in which the animal body is compared to the spirit. For ordinary references to the body, corporal is the usual word. For example, one might refer to “the corporeal existence of Jesus,” but to “corporal punishment.”
6. denote / connote
“To denote” means “to indicate.” “To connote” means “to imply or suggest.” A squiggly red line under a word in a corrected essay denotes a misspelled word. Words like Mother and home connote warmth and comfort.
7. deserts / desserts
In the idiom “to get one’s just deserts,” the word deserts is often misspelled as desserts. For other uses and pronunciations of desert and dessert, see this post: Just Deserts vs Just Desserts.
Read more here: http://www.dailywritingtips.com/top-ten-confused-words-c-d/