This glossary is a selective list of confusing words that writers commonly misuse in formal or technical papers. Sometimes the errors are acceptable in casual speech or informal writing. For a more comprehensive list of “Notorious Confusibles,” see the Capital Community College’s online Guide to Grammar & Writing:


Alternate means one after the other.

Example: When you make lasagna, place alternate layers of pasta, mozzarella cheese, and sauce into a baking pan.

Alternative means one or the other.

Example: Students could write a paper as an alternative to taking the exam.


Affect is a verb meaning to change or influence.

Example: The drug did not affect his driving.

Effect is usually a noun meaning result or outcome.

Example: In fact, the drug seemed to have no effect at all.

Effect can occasionally be a verb meaning to bring about.

Example: Her efforts effected a change.


Use amount for an aggregate that does not have countable units.

Example: Restoring the damaged coast will take a tremendous amount of time and money.

Use number whenever you can count the units.

Example: The town can take a number of precautions to reduce future flooding.


Assure means to encourage, to promise.

Example: The agent assured us that the house is not on a flood plain.

Ensure means to make certain.

Example: To ensure that the house was not on a flood plain, I consulted city council maps.

Insure is used when referring to legal and financial protection.

Example: The house is on a flood plain, so I may have trouble getting it insured.


Bad is an adjective meaning “not good,” “sick,” or “sorry.”

Examples: In spite of the medicine, I still feel bad.
She felt bad about losing her mother’s ring. 

The verb feel is a linking verb, and the adjective bad is a subject complement.

Badly is an adverb meaning “not well.” Used with “want” or “need,” badly means “very much.”

Examples: The fans badly wanted a victory.
We played badly during the first half of the game.


Between is associated with two, as in a comparison.

Example: Let’s keep this secret between the two of us.

Among is used with three or more.

Example: We can’t keep this secret among the ten of us.


Complement means to fill up or make complete.

Example: Her technical knowledge complemented his communication skills.

Compliment means praise or respect.

Example: We complimented the team for its excellent presentation.

comprises/composed of

Comprise means to embrace or to include.

Example: The whole comprises its parts.

Compose means to form by putting together.

Example: The committee is composed of three representatives.


Continual means constantly recurring.

Example: Most movies on television are continually interrupted by commercials.

Continuous means unceasing.

Example: Cable television often presents movies continuously without commercials.

datum/data and data/results

Datum is singular.

Data is plural.

The numbers you collect as you conduct your experiment are data. After you finish your computations, they become results. The data and the results are the same only if the procedure does not involve computations.

et al.

The abbreviation et al. stands for et alia, which means “and others.”

In APA style, if you have three, four, or five authors in a text citation, list all their names when you cite the group for the first time:

Example: … (Dukenfield, West, Keaton, 2004).

After the first text citation, you use et al. to shorten the reference:

Example: … (Dukenfield et al., 2004)

If you have more than six authors, you may use et al. to shorten all the text references, including the first. In the References section, however, you should write out the first six names:

Dukenfield, W. C., West, M., Keaton, B., Marx, J., Lloyd, H., Kaye, D. et al.


Use fewer if you can count the number of units.

Example: There are fewer students enrolled in the 8:00 class.

Use less for amounts that cannot be counted.

Example: We used less cement for the last job.


Good is an adjective meaning to have a good time or to give a good performance.

Well is properly used as an adjective to refer to health.

Examples: You don’t look well today.
Since my illness, I haven’t felt well.
My grandfather hasn’t looked well since his operation.

Well means “ably” when it functions as an adverb.

Examples: The team played well during the first half of the game.
She ran well for the first twenty miles, but then she collapsed.
Peter did so well in practice that the coach decided to put him in the starting lineup for the opening game.

input/enter Input is a noun, which is often used incorrectly as a verb.

Enter is a verb.

Example: He entered the input into the database.


Irregardless does exist in dictionaries, but it is considered nonstandard” or “casual” English usage.

Regardless as an adverb means “notwithstanding.”

Example: Regardless of the fact that the word “irregardless” appears in the dictionary, you should avoid using it in formal reports. 7


Its is a possessive pronoun.

It’s is a contraction for “it is.”

over/more than

In the USA, use more than instead of over when you have countable, numeric units.

Example: The experiment produced more than 100 units.


Principal means first, highest, chief, or most prominent in importance.

Example: Dr. Smith is the principal researcher on that project.

principle is a basic truth, law, or assumption.

Example: The calculations are based on fundamental principles of physics. 


Unique means the only one of its kind. The phrase “very unique” is redundant.