Tricky Words: Commonly Confused Words in American English

Most writing mistakes aren’t spelling mistakes. They’re real words in the wrong place: their where you meant there, affect where you needed effect, lose typed as loose. Spell-check waves them through because every one of them is in the dictionary.

This guide collects the word pairs that cause the most trouble in American English and groups them by why they’re confusing. Each entry gives you a plain rule, a real example, and, where possible, a memory trick you can use in the middle of a sentence.

Bookmark it, skim the tables, and come back whenever a word looks “off.” For sentence-level rules like subject-verb agreement, see our grammar rules guide.

Sound-Alikes: Same Sound, Different Meaning

These pairs sound identical (or nearly so) when spoken, so your ear can’t help you. You have to know the meaning.

Affect vs. Effect

In everyday writing, affect is usually a verb (to influence) and effect is usually a noun (a result).

• The rain affected our travel plans.
• The rain had a big effect on our travel plans.

Memory trick: Affect is the Action; Effect is the End result.

There are two exceptions worth knowing. Effect as a verb means “to bring about”: The new manager effected real change. And affect as a noun is a psychology term for visible emotion, pronounced with the stress on the first syllable (AFF-ect): The patient showed a flat affect. Our deep dive on affect vs. effect covers more edge cases.

More Sound-Alikes

Memory trick: A complement completes something. A principle is a rule. Stationery has an e for envelopes; stationary has an a for standing still.

One more: complimentary also means “free.” The hotel offers complimentary breakfast. It is never complementary breakfast, unless the breakfast completes something.

And it’s always “piqued my interest,” not “peaked” or “peeked.” Interest gets stirred up, not climbed or glanced at.

Contractions vs. Possessives

The apostrophe is the source of most of these errors. The rule is simpler than it looks: in a pronoun, an apostrophe means letters are missing. Possessive pronouns (its, your, their, whose) never take one.

There is the odd one out: it’s a place or a sentence starter, not a possessive. Put it over there. There are three reasons.

Quick rule: Read the word as “it is,” “you are,” or “they are.” If the sentence still works, use the apostrophe. If not, drop it.

Try it: The company lost (it’s/its) best client. “The company lost it is best client” makes no sense, so the answer is its. Our post on its vs. it’s walks through more examples, and the punctuation guide covers apostrophes in general.

Verbs That Trip People Up

Lay vs. Lie

This is the hardest pair in the language, because the past tense of lie is lay.

• Lie means to recline. It never takes an object. I need to lie down.
• Lay means to put or place something. It always takes an object. Lay the book on the table.

• Yesterday I lay on the couch all afternoon. (past of lie)
• Yesterday I laid my keys on the counter. (past of lay)

Memory trick: Lay has an a, like place. If you could replace it with “place” or “put,” use a form of lay.

(The lie that means “say something untrue” is regular: lie, lied, lied.) See our full lay vs. lie breakdown for practice sentences.

Loose vs. Lose

Lose (one o) means to misplace or fail to win. Loose (two o’s) means not tight.

• Don’t lose your ticket.
• This screw is loose.

Memory trick: Lose lost an o.

Ensure vs. Insure vs. Assure

• Ensure means to make certain. Double-check the numbers to ensure accuracy.
• Insure means to cover with insurance. We insured the car.
• Assure means to promise or reassure a person. I assure you the report is ready.

Merriam-Webster allows insure in the “make certain” sense, but AP and most US editors reserve insure for insurance. Keeping them separate is the clearest choice.

Quick rule: You assure people, you ensure outcomes, and you insure property.

Who vs. Whom and Other Pronoun Traps

Who is a subject (like he). Whom is an object (like him).

• Who wrote this? (He wrote this.)
• To whom should I send it? (Send it to him.)

Memory trick: If you can answer with him, use whom. Both end in m.

For clauses, answer the question inside the clause only: Hire the person who you think is best. Ignore “you think,” and you get “he is best,” so who is correct. In casual American speech, who often replaces whom entirely, and that’s fine in conversation. In formal writing, use whom after prepositions. Our who vs. whom guide covers the tricky cases.

Then vs. Than

Then is about time or sequence. Than is for comparisons.

• We ate, and then we left.
• This route is faster than the highway.

Memory trick: Then is about when. Than is for comparisons.

Quantity and Distance

Fewer vs. Less

Use fewer for things you can count one by one. Use less for amounts you measure.

• Fewer emails, fewer people, fewer mistakes
• Less water, less time, less stress

There’s a well-known exception: use less with time, money, distance, and weight when you’re treating them as a single amount. The drive takes less than 20 minutes. It costs less than $50. You’re thinking about one total, not 50 individual dollars.

Quick rule: If you can put a number in front of the noun (three emails), use fewer. If you can’t (three waters), use less.

Farther vs. Further

In American English, farther is for physical distance and further is for figurative distance or “additional.”

• Our hotel is farther from the beach than I expected.
• Let’s discuss this further on Monday.
• Do you have any further questions?

Memory trick: Farther contains far, which you can measure in miles.

When the line blurs (Nothing could be further from the truth), further is the safer pick, since it can cover both senses.

Spacing Traps: One Word or Two?

Some words change meaning depending on whether you write them as one word or two.

Quick rule: If you can insert “single” between the words (every single day), write two words. After a preposition such as for or in, always write a while.

Anyway vs. Anyways

Anyway is the standard form. Anyways is common in casual speech, but dictionaries label it informal or dialectal. Keep it out of emails, essays, and reports.

Toward vs. Towards

Both are correct. Toward is the standard American form; towards is more common in British English. The same goes for afterward, backward, and forward. More differences like this are in our American vs. British English guide.

Latin Abbreviations: i.e. vs. e.g.

These two get swapped constantly, and the mix-up changes your meaning.

Memory trick: i.e. = “in essence.” e.g. = “example given.”

In American style, both take periods and are usually followed by a comma, and many editors prefer them inside parentheses. Chicago recommends a comma after each. Don’t add “etc.” after an e.g. list; “for example” already tells readers the list isn’t complete.

Words That Aren’t Words (or Aren’t Standard)

Alot

Alot is not a word. Write a lot, two words. (Allot, meaning to distribute, is a real but different word.)

• Wrong: I have alot of work.
• Right: I have a lot of work.

Could of, Should of, Would of

These come from mishearing the contractions could’ve, should’ve, and would’ve. The correct form is always have.

• Wrong: I should of called.
• Right: I should have called. / I should’ve called.

Irregardless

Irregardless appears in Merriam-Webster and other dictionaries, so it’s technically a word, but it’s labeled nonstandard. The ir- and -less cancel each other out. Use regardless.

Literally

Literally traditionally means “actually, in a literal sense.” It’s also widely used as an intensifier (I literally froze), and dictionaries now record that use. But plenty of readers find it sloppy.

• Right: The building was literally on fire. (It was.)
• Risky: My boss literally exploded. (Unless something went very wrong.)

Quick rule: In professional writing, use literally only when you mean it, well, literally.

Quick Checklist

Before you hit send, scan for these:

• Its/it’s, your/you’re, their/they’re: Expand to “it is,” “you are,” “they are.” Apostrophe only if it still makes sense.
• Affect/effect: Verb? Usually affect. Noun? Usually effect.
• Then/than: Time = then. Comparison = than.
• Lay/lie: Could you swap in “place”? Use lay/laid. Otherwise lie/lay/lain.
• Who/whom: Answer with him? Use whom.
• Fewer/less: Countable = fewer. Measured amount = less.
• Farther/further: Physical distance = farther.
• i.e./e.g.: “That is” vs. “for example.” Comma after both.
• No alot, could of, or irregardless. Write a lot, could have, regardless.
• Ensure/insure/assure: Outcomes, insurance, people.

Keep this list handy, and you’ll catch the errors spell-check misses. GrammarVista.com USA adds new word pairs regularly, so check back when you hit one that isn’t here.