Fitful, fitfully – The adverb is more common and is often used to describe sleep. “I slept fitfully.” While it might sound that I slept really well and had a very restful night, the actual meaning is the opposite. It is actually derived from the meaning of “fit” that means a spasm or a spasmodic episode. And so the actual meaning is that I tossed and turned all night.

Spendthrift – This noun seems to describe someone who keeps their money to themselves and is thrifty with their spending. In fact, it means the opposite, a spendthrift is someone spends money recklessly.

Inflammable – Usually the prefix “in” means the opposite of the version of the word without the prefix. In the case of inflammable, it is not the word flammable with a prefix added, it is actually an adjective derived from the separate verb “to inflame” which has an old-fashioned meaning of “to set fire to”. So flammable (derived from flame) and inflammable (derived from inflame) mean the same thing.

Prefer the familiar word to the far-fetched.

Prefer the concrete word to the abstract.

Prefer the single word to the circumlocution.

Prefer the short word to the long.

Prefer the Saxon word to the Romance.

And while he said it in 1908 in The King’s English (2nd Ed.) it is still true today. If you prefer your rules in the negative then try this:

Never use an unusual word where a familiar word will do.

Never use an abstract term when you can use a concrete one.

Never use a phrase where one word will do.

Never use a long word where a short word will do.

Never use a Romance word where there is a Saxon equivalent.

Let’s take each in turn and look at an example or two.

•  Never use an unusual word where a familiar one will do.
  You could eat al fresco, but more people will understand you if you eat outside. Foreign words are the biggest cause of falling foul of this rule. On the other hand, why say flaccid when you can say limp?
• Never use an abstract term when you can use a concrete one.
  A lot of slang comes into this category. When you say something like “We were behind the eightball all through the game”, I hope you were playing pool. Otherwise it is better to simply say: “The opposition was ahead of us for most of the game.”
• Never use a phrase where one word will do.
  Don’t use a blunt, flat-bladed, long-handled agricultural instrument to dig your potatoes. Use a spade.
• Never use a long word where a short word will do.
  This very often crosses over with the last rule (see below). Too many people think that using a long word where a short one will do makes them look intelligent. What it usually means is that they often look rather silly, because almost all words in English have shades of meaning or voice, and to use a word you don’t understand can lead to you looking rather foolish. On the othert hand, some have exactly the same meaning. Prefer “use” to “utilise”, “orient” to “orientate”, “flammable” to “inflammable”…
• Never use a Romance word where a Saxon word will do.
  A Romance word is one that has come down to us through the Latin and French influence upon English. In this case it means: of the Romans; it doesn’t mean that your heart will start fluttering. Very many Romance verbs are long words and their equivalent Saxon verb is short: compare “actuate” and “do” or “initiate” and “start”.  If you read the works of JRR Tolkien you’ll notice his elegant prose comes very much from his choice of the Saxon rather than the Romance.

No.

There are people who will say that less should be used with uncountable nouns and fewer should be used with countable nouns. In effect, there is a ‘rule’.

I have less water than you. Water is an amount, not countable.

I have fewer marbles than you. Marbles can be counted.

But the OED says this in its definition of ‘less’:

▸ a A smaller number of; fewer. Now non-standard. OE. ▸ b Of number, amount, degree, etc.: not so great (as something mentioned or implied).

The first implies that using less for countable nouns was once acceptable but is not non-standard. So the ‘rule’ works. So far so good.

But the second definition states that less can be used with countable nouns as long as another number has already been mentioned or implied.

This means that the sentence ‘ten items or less’ is perfectly good standard English, since the number ten has already been stated. In effect, you can’t count the number of items, since it can be any number from one to ten. This could mean that the ‘rule’ still works. Try these: Any number fewer than ten? Any number less than ten? Most people would say the second sentence is better.

Apparently, supermarkets are so fed up with people not understanding the whole meaning of the word and applying the limited ‘rule’ that they are bowing to pressure. They are now changing their signs to ‘ten items or fewer’. This may change the usage, who knows. But they weren’t wrong, they were just victims of one of the few ‘rules’ in English that generally works, and that most people can remember. The trouble is they don’t ever get taught the exceptions.

And let us remember the point of communication. Is it possible to misinterpret the phrase: “Ten items or less”? No it isn’t. You can argue with it, but you can’t fail to understand it.