Thought this was fun . . . yoinked it from Heather's LJ

I read through this, and found only one that I definitely know I use improperly (criteria vs. criterion), but I might inadvertently use a few others from time to time without realizing I have.

The Inigo Montoya Guide to 27 Commonly Misused Words
by Brian Clark

You keep using that word. I do not think it means what you think it means. ~Inigo Montoya, The Princess Bride

It may be inconceivable for you to misuse a word, but a quick look around the web reveals plenty of people doing it. And it’s all too easy when we hear or see others use words incorrectly and parrot them without knowing it’s wrong.

We know by now that great copy and content often purposefully break the rules of grammar. It’s only when you break the rules by mistake that you look dumb.

So let’s take a look at 27 commonly misused words. Some are common mistakes that can cost you 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
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
Criteria is plural, and the singular form is criterion. If someone tells you they have only one criteria, you can quickly interject and offer that it be they get a clue.

Farther / Further
Farther is talking about a physical distance.

“How much farther is Disney World, 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.

Hopefully
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.

Smart: I hope she says yes.
Wrong: Hopefully, she says yes.
Wrong: Hopefully, the weather will be good.
Smart: It is hoped that the weather cooperates.
Smart: She eyed the engagement ring hopefully.

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?

Irregardless
Irregardless is not a word. Use regardless or irrespective.

Literally
“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 8: George 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.

Towards
Towards is wrong in American English. It’s toward. I went 41 years not being sure about this one.

Unique
Unique means (literally) one of a kind. Saying something is very or truly unique is wacked. 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.

Subjects:

Who wrote this blog post?
Who is speaking at the conference?
Who is going to clean up this mess?

Objects:

Whom are you going to write about?
Whom did he blame for the Google Slap?
Whom did he bait for the links?