One of the most common uses for the hyphen (-) is to connect compound modifiers. A compound modifier is a mix of two or more adjectives or adverbs that jointly modify the same word. So, for example:
He is such a well-behaved boy.
The words well and behaved work in tandem to modify boy. Well clarifies the meaning of behaved, and together they carry a new descriptive meaning. They are acting together as though they were a single adjective. Here are some other examples:
“You think she committed the murder? She’s a ninety-seven-year-old woman, for heaven’s sake!”
“My hospital takes a very patient-centered approach to healthcare.”
“The creature had a 50-foot wingspan!”
Note that in compound modifiers that involve numbers, a hyphen is required whether you spell out the number or use numerals (so the last example could also be fifty-foot; but a hyphen is needed either way).
Part of the reason for this rule is to avoid potentially confusing situations. For example:
“We met an American football player in the pub last night.”
Did the speakers meet someone who plays American football, or did they meet a football player who is also American? A hyphen can add clarification:
“We met an American-football player in the pub last night.”
The hyphen lets us know that those two descriptors belong together; thus, the answer is that the speakers met someone who plays American football.
|"Man eating plant" vs. "Man-eating plant."|
Remember that you only hyphenate words that are working together as a single adjective. So the following usage would be incorrect:
“This might be the most well-thought-out-and-over-detailed plan I’ve ever seen.”
Well-thought-out and over-detailed are two separate descriptions, so the example should instead read:
“This might be the most well-thought-out and over-detailed plan I’ve ever seen.”
Sadly, it can’t just be that simple. There are a few exceptions to the hyphenating-compound-modifiers rule.
First exception: If the first word in the compound modifier is an adverb that ends in -ly, it is extremely unusual to hyphenate the two words together.
He is such a poorly behaved boy.
Part of the reason for this rule is to avoid potentially confusing situations.
Second exception: This rule only applies to compound modifiers that appear before the word they modify. If they appear after, they should not be hyphenated. Here’s what some of our earlier examples would look like if the compound modifiers had appeared after the word they modified:
“That boy is so well behaved.”
“You think she committed the murder? That woman is ninety seven years old, for heaven’s sake!”
“My hospital’s approach to healthcare is very patient centered.”
“The creature had a wingspan of 50 feet!”