A compound modifier consists of two words that act together as one unit to modify a noun.

Here are some examples:

The sweet-smelling doughnut made my tummy grumble.
(Here sweet and smelling work as one unit to describe the noun doughnut.)

He had to wash his mud-covered ninja outfit.
(Mud and covered work together to explain the noun outfit.)

Their favorite wand was the glitter-speckled one.
(Glitter and speckled are one unit modifying the noun one.)

You’ll notice that in the examples above, all of the word sets are hyphenated: sweet-smelling, mud-covered, glitter-speckled. But there are times when the word sets aren’t hyphenated.

Compound Modifiers Ending in -ly
Compound modifiers that include an adverb ending in the suffix -ly do not get hyphenated. Why is this? Here is how The Chicago Manual of Style (the rulebook people use to edit books) explains it in section 7.86:

Compounds formed by an adverb ending in -ly plus an adjective or participle (such as largely irrelevant or smartly dressed) are not hyphenated either before or after a noun, since ambiguity is virtually impossible. (The -ly ending with adverbs signals to the reader that the next word will be another modifier, not a noun.)

For the non-editors reading this, what that means is the reader will know instinctually that the word coming after the -ly is working with the -ly word to describe something. So it doesn’t need the hyphen to help readers understand it is a word pair.

Now let’s look at some examples:

The cowboy sauntered into the dimly lit saloon.
(Dimly and lit both work together to explain saloon. But since dimly ends in -ly, it doesn’t use a hyphen. A reader should automatically understand lit goes with dimly.)

The professor’s terrifyingly large stack of papers to grade made him anxious.
(Here terrifyingly and large work together but do not require a hyphen to link them.)

His awkwardly long tie made people question his fashion sense.
(Awkwardly works with long and does not need a hyphen.)

Now you know when to use your trusty hyphen with compound modifiers. Go forth and hyphenate correctly!

Erin Servais has been slinging hyphens as a book editor for ten years. To learn more about her and how to hire her for your book project, go to her website: www.dotanddashllc.com.