The Inigo Montoya Guide to 27 Commonly Misused Words, written by Brian Clark, Founder of Copyblogger
27 commonly misused words… some are common mistakes that distract when trying to keep a reader’s attention. Others are more obscure and just interesting to know.
Adverse / Averse
Adverse means unfavorable. Averse means reluctant.
Afterwards is wrong in American English. It’s afterward.
Complement / Compliment
I see this one all the time. Complement is something that adds to or supplements something else.
Compliment is something nice someone says about you.
Criteria is plural, and the singular form is criterion.
Farther / Further
Farther is talking about a physical distance.
“Move farther away from those people, Daddy!”
Further is talking about an extension of time or degree.
“Take your business further by reading Copyblogger.”
Fewer / Less
If you can count it, use fewer. If you can’t, use less.
“James has less incentive to do what I say.”
“Tony has fewer subscribers since he stopped blogging.”
Historic / Historical
Historic means an important event. Historical means something that happened in the past.
This word is used incorrectly so much (including by me), it may be too late. But let’s make you smarter anyway.
The old-school rule is you use hopefully only if you’re describing the way someone spoke, appeared, or acted.
Imply / Infer
Imply means to suggest indirectly (you’re sending a subtle message). To infer is to come to a conclusion based on information (you’re interpreting a message).
Insure / Ensure
Insure is correct only when you call up Geico or State Farm for coverage. Ensure means to guarantee, and that’s most often what you’re trying to say, right?
Although Irregardless may now be grudgingly considered a word, better to use regardless or irrespective instead.
“I’m literally starving to death.”
No, odds are, you’re not.
Literally means exactly what you say is accurate, no metaphors or analogies. Everything else is figurative (relative, a figure of speech).
Premier / Premiere
Premier is the first and best in status or importance, or a prime minister.
Premiere is the opening night of Star Wars 15: Disney Wants More Money.
Principal / Principle
Principal when used as a noun means the top dog; as an adjective, it means the most important of any set.
Principle is a noun meaning a fundamental truth, a law, a rule that always applies, or a code of conduct.
Then / Than
Use then when referring to points in time (“I did this, then I did that”). Use than when comparing (“I’m better than that”).
Unique means (literally) one of a kind. Saying something is very unique incorrect… it’s either a purple cow or it isn’t.
Who / Whom
This one is a lost cause, but let’s go down swinging. The way to deal with the who versus whom quandary is a simple substitution method.
First, a refresher on subjects and objects.
Subjects do the action:
“He/she/we like(s) to rock the house.”
Objects receive the action:
“The rock star sneered at him/her/us.”
Use who for subjects and whom for objects.
Truth is, whom just doesn’t sound right in many situations where it’s correct, especially in the US. You now know the rule … feel free to break it.
(I left the links from the article as they lead to similar blog posts I thought you might find helpful.)