Coordinate adjectives, or paired adjectives, are two or more adjectives that precede and describe the same noun and are equal in their application to the noun. In other words, neither adjective carries more weight in describing the noun.
If two or more adjectives are coordinate, a comma is used to separate them to provide clarity. If you can replace the comma with the word “and” and reverse the order of the adjectives, the comma is necessary. Check out the below examples:
Example 1 (CORRECT):
Example 2 (INCORRECT):
In the first example, the adjectives “slippery” and “treacherous” are interchangeable; neither carries more weight in describing the roads, so the comma between the two adjectives is correct. In the second example however, the adjectives “pink” and “cashmere” are not easily swapped, as “cashmere” carries more weight. Likewise, writing “pink and cashmere sweaters” is both grammatically incorrect and nonsensical; these adjectives are called cumulative adjectives and do not require commas.
Sometimes more than two adjectives are used to describe or modify the same noun. When these adjectives follow the rules for coordinate adjectives, commas are used between at least two of the adjectives, with the last pause between adjectives shown as a comma or through using the word “and.” Consider this example:
There are even some cases where three adjectives are used where two of the three are coordinate and one is not. See the below example:
“Pink” and “lacey” are coordinate because they are easily switched, and the word “and” can replace the comma. However, “dancing” is not coordinate because it carries more weight in modifying the noun, “shoes.” It would not make sense to write “pink and lacey and dancing shoes.” In this case, the comma is only needed between the first two adjectives.