Importance of hyphens

A hyphen is a punctuation mark that plays distinct roles in the English grammar. Although it looks like a dash, it is used as a joiner for words; a dash, on the other hand, is used to push two words apart.
Hyphens have three main roles.
1. Joining prefixes
Using a hyphen to join prefixes with words is becoming less common; prefixes are now combined with words to form standalone words. Sometimes, this may change your intended meaning and distort the message you want to convey.
Example: “We re-covered a pillow” vs. “We recovered a pillow”
Clearly, an ambiguity exists. And a hyphen, when used to join prefixes, would help overcome this ambiguity.
2. Forming compound words
Compound adjectives (descriptive words)
Examples: up-to-date records, three-month-old baby
However, a few exceptions to this case exist.
- No hyphens to be used in compound adjectives when the first word ends in ‘ly’.
Example: Rapidly moving object, and not rapidly-moving object - No hyphens to be used when the adjective comes after the noun it would modify.
Example: Real-time update, and update in real time
Example: blow-dry
However, a few exceptions to this case exist.
Example: Proofread is one word. It is important to refer to current grammar trends and styles if unsure.
Another exception is for phrasal verbs.
Example: To address the frustration built up (not built-up) due to the lack of understanding, the team decided to take a short break.
The flat’s built-up area (not built up area) was not a lot. This is because built-up forms an adjective in this case.
Compound nouns (things)
Compound nouns can be written as a single word, two words, or a hyphenated word. Refer to a dictionary for acceptable usage, when unsure.
3. Indicating word breaks
When fitting an entire word at the end of a line is not possible, especially if you are hand-writing a document, a hyphen is used before ending the word on the next line.