A single adjective made up of more than one word is called a compound adjective.|
The parts of a compound adjective are often joined together with hyphen(s) to show it is just one adjective (e.g., a four-seater aircraft, a double-glazing salesman).
However, it is possible to group the words in a compound adjective using title case if it's a title (e.g., Billy Elliot tickets), italics (especially if it's a foreign term) (e.g., ab initio course), and quotation marks (e.g., a "get out now" look).
Alternatives to Hyphens in Compound AdjectivesAlthough hyphens are most commonly used to link the parts of a compound adjective together, this linking can also be done with title case (i.e., the use of capital letters), italics, quotation marks, or a combination of these.
Here are some examples:
JUST LINK THE PARTS OF THE ADJECTIVE
It is a mistake to join the adjective and whatever is being described with a hyphen.
should be "30-year sentence"
In the same way, it is a mistake to include the thing being described within the quotation marks, the italics, or the title. For example: