Does anyone have a rule of thumb for using hypens in compound adjectives, such as “life-threatening situations”?
My rule of thumb is that if you’re using a phrase as an adjective, the words in the phrase should be connected by hyphens. I think it always makes your meaning clearer, even if it sometimes looks a little stuffy. For example: if I said you asked an effective communication question, it’d be unclear whether I meant an effective question about communication or a question about effective communication, but effective-communication question makes it clear.
These rules (from The Legal Writing Teaching Assistant: The Law Student’s Guide to Good Writing, by Professor Marc A. Grinker, a good grammar site, complete with exercises!) are short and sweet, and seem correct to me: Compound Adjectives 1. A compound adjective is formed when two or more adjectives work together to modify the same noun. These terms should be hyphenated to avoid confusion or ambiguity. Incorrect: The black and blue mark suggested that he had been involved in an altercation. Correct: The black-and-blue mark suggested that he had been involved in an altercation. Incorrect: Her fifteen minute presentation proved decisive to the outcome of the case. Correct: Her fifteen-minute presentation proved decisive to the outcome of the case. 2. However, combining an adverb (usually a word ending in “ly”) and an adjective does not create a compound adjective. No hyphen is required beca
