One of the biggies, here: fewer or less? Many people, including a good friend of mine, get absolutely incensed when these are used incorrectly (leading to the spectacle of several well-educated, intelligent ladies self-correcting nervously when they make a slip in front of her: she probably doesn’t warrant this fear any more than I warrant the fear people apparently have of making a typo in a response to this blog!)
Anyway, it’s quite simple …
Fewer is used for countables. Less is used for mass nouns denoting things that can’t be counted – uncountables.
So – it should be “5 items or fewer” on that supermarket checkout sign. Less coinage has been produced this year, but there are fewer coins. Less hair has been cut off this time, but I have fewer grey hairs than he does.
The Concise Oxford English Dictionary is reassuringly stern on this one: “The use of less with a count noun (“less people”) is incorrect in standard English.” That’s told you!
You can find more troublesome pairs here.
LibroEditing proofreading, editing, transcription, localisation 
Gill Rose
July 11, 2011 at 5:39 pm
I’ll just put my glasses on the end of my nose and give you my famous stare over the top of them!
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Liz at Libro
July 12, 2011 at 6:41 am
Someone’s got to keep the standards up! I saw a “10 items or fewer” sign in a supermarket yeasterday and nearly took a photo!
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Kate
July 11, 2011 at 9:21 pm
I am beginning to think ‘what did Liz say in her blog’ now when wondering about which word to use when writing at work and home (still have to think really hard about apostrophe’s though as I know there are so many people who will red mark me when I get it wrong.
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Liz at Libro
July 12, 2011 at 6:43 am
Thanks, Kate – that’s a lovely thing to read! Do let me know if there are other pairs you’d like to see me write about! Um … no apostrophes with plurals though, seeing as you mention them.
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Jane
July 12, 2011 at 7:55 am
The thing that always troubles me about this one (and if you can give me a way to get round it I shall be eternally grateful) is what is countable and what is not. Is it the possibility of being countable? In that case, you could if you had nothing better to do, count the hairs on someone’s head, but fewer hair just sounds wrong. Ditto coinage. You could go out there and count it.
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Liz at Libro
July 16, 2011 at 4:46 pm
I suppose the way to think of it might be that an uncountable is a collective noun. So “hair” is a collective noun, collecting together all the individual hairs but making it so you don’t need to count them. “Coinage” is a collective noun for coins. Does that help?
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