The Principal Problem (and other sneaky slip-ups)

The invitation email was confident and clear – until the conference host kindly offered a complementary place at the event. Very generous… except what they meant was complimentary (i.e. free, not matching!).

The project report? Professional, well-structured, and ready to go – until someone spotted that the team was stationery on site. Unless they were sitting around as pens and notepads, that probably wasn’t quite right.

And the academic paper? “The principle aim of the study…” made a compelling argument. But what they really meant was principal – as in, the main focus.

These aren’t rookie errors. They’re the kind of everyday slips that sneak in when we’re working fast, re-reading drafts for the tenth time, or juggling a dozen other tasks. And because both words in each pair are spelled correctly, spellcheck isn’t going to save you.

Here’s a closer look at the usual suspects – and how to remember which is which:

1. Compliment vs. Complement

• Compliment (with an “i”) is something nice you say to someone.

  “She gave a lovely compliment about the presentation.”

• Complement (with an “e”) means something that goes well with something else.

  “The wine complemented the meal perfectly.”

  Tip: Think of the “i” in “compliment” as standing for “I like your tie!”

2. Affect vs. Effect

• Affect is usually a verb – to influence or change something.

  “The weather can affect your mood.”

• Effect is usually a noun – the result or outcome of something.

  “The new policy had a positive effect on staff morale.”

Tip: A = Action (Affect is a verb). E = End result (Effect is a noun).

Just to complicate things further, there are certain circumstances where affect can be a noun and effect can be a verb, so it's always best to check, and - if in doubt - ask me!

3. Advice vs. Advise

• Advice is a noun meaning guidance or recommendations.

  "She gave sound advice on project planning."

• Advise is a verb meaning to offer suggestions or counsel.

  "I advise reviewing the terms carefully."

Tip: Advice is a thing  - like ice (both end in -ce).  Advise is something you do – and verbs do things. (This one’s tenuous, I know, but I couldn’t think of anything else, so please just go with it..!) 

4. Stationary vs. Stationery

• Stationary (with an “a”) means not moving.

  “The car was stationary at the traffic lights.”

• Stationery (with an “e”) refers to paper, pens, and office supplies.

  “She bought some new stationery for the office.”

  Tip: Think of the “e” in stationery for “envelope.”

5. Principal vs. Principle

• Principal can mean the head of a school, or the most important person or thing.

  “The principal reason for the decision was safety.”

• Principle is a fundamental truth, rule, or belief.

  “He stuck to his principles.”

  Tip: Your school principal is your “pal” – principal = person or main thing.

So, how do you stop these mistakes from sneaking into your work?

Even seasoned writers trip over these kinds of words, especially when you're rushing or reading your own work too often. But there are a few tricks that can make a real difference:

• Take a break before reviewing – you’ll come back with fresher eyes.

• Read aloud – you’ll hear mistakes you might not see.

• Don’t rely solely on spellcheck – it won’t flag a real word used incorrectly.

• Get a second pair of eyes – especially for important documents.

Even editors need editors – because spotting these errors when you’ve written the piece yourself is a lot harder than it looks.

Need a fresh perspective on your writing? Whether it’s a report, a proposal, or your whole website, I can help you make sure your content is as professional and polished as you are.

Get in touch or connect with me on LinkedIn.

PS: The word I always have to double-check? Complimentary vs. complementary. Every. Single. Time. What’s yours?