Missing Hyphens

1. “He’s a world class sexist.”
As written, this sentence states that the person referred to in the subject is a class sexist (whatever that is) of the world variety (whatever that means). The simple insertion of a hyphen between the two words preceding the noun sexist signals that together, they describe what kind of sexist the person is: “He’s a world-class sexist.”

2. “The project exemplifies his wheeling and dealing ways.”
Without commas, this sentence reads as if it is discussing two characteristics of the person in question: his wheeling and his dealing ways, but it pertains to his ways of wheeling and dealing, so the words in that phrase must be linked with hyphens to clarify their unity: “The project exemplifies his wheeling-and-dealing ways.”

3. “She claims she did it in self defense.”
Most adjectival phrases, like “world class,” are hyphenated before the noun they modify but are open compounds when they follow a noun or stand on their own, though there are exceptions in both cases. Phrases beginning with self, however, are anomalous. Hyphenate them always, as in “She took a self-defense class,” and here: “She claims she did it in self-defense.”

4. “Smith accused Jones of a coverup.”
Style for compound words that consist of a preposition and another word are maddeningly inconsistent. Those ending with the word up, for example, haphazardly include or omit a hyphen — and it’s not easy to guess, based on appearance, which form is correct. For example, buildup and markup would seem to merit hyphens, but they’re closed. Meanwhile, cover-up is hyphenated (as is runner-up). When in doubt, look up the word. The sample sentence here should read, “Smith accused Jones of a cover-up.”

5. “It’s a byproduct of our times.”
By-product is one of a handful of noun/noun compounds that retains a hyphen: “It’s a by-product of our times.” This type of error is the hardest to catch, because it relies on prior knowledge of the few exceptions to the rule that a noun/noun compound is either open or closed (which provides a challenge in itself). The best solution is to read high-quality content, which is likely to treat such constructions correctly — but not everyone has the aptitude for retaining information like this. (That’s why we have editors.)