When do you put commas between adjectives?
When you use a string of adjectives, you often separate the adjectives with commas, as in “He is tall, dark, and handsome.” Sometimes, though, you don’t use a comma between two adjectives.
Coordinate Adjectives Versus Cumulative Adjectives
The comma rule comes down to the difference between two kinds of adjectives: coordinate adjectives and cumulative adjectives. Coordinate adjectives are adjectives in a row that each separately modify the noun that follows (1), as in “heavy, bulky box.” Both “heavy” and “bulky” modify “box.” You can even rearrange the adjectives and say, “bulky, heavy box.”
Cumulative adjectives, on the other hand, don’t separately modify the noun that follows even though they are all stacked up before the noun too (2). Instead, the adjective right before the noun pairs with the noun as a unit, and then adjective before that unit modifies that. An example will make this more clear: In the phrase “exquisite custom houseboat,” “custom” modifies “houseboat”—they become a unit—and then “exquisite” modifies “custom houseboat.”
If you try to rearrange the adjectives as we did for “heavy, bulky box,” you’ll run into a problem. The phrase “custom exquisite houseboat” is awkward, and it’s awkward precisely because you can’t rearrange cumulative adjectives.
Let’s say you have two adjectives in a row before a noun and you’re not sure whether they’re coordinate or cumulative. You can perform a simple test: Add the word “and” between the adjectives. If the phrase makes sense, the adjectives are coordinate; if not, they’re cumulative. For example, “It’s a bulky and heavy box” makes good sense but “It’s an exquisite and custom houseboat” does not.
Here’s a quick review so far: You can rearrange coordinate adjectives, and you can stick an “and” between them. As for cumulative adjectives, neither trick works.
Next: How to Figure Out Cumulative Adjectives