What would English grammar be without exceptions? Apparently nothing, because the rules for the correct use of hyphens include exceptions!
Rules for compound adverb/adjective modifiers:
1. The two-word modifier comes before the noun (just like in this sentence!).
2. Both words function together to modify the noun. The hot, red car was fast. Hot car. Red car. But the red-hot car was fast. Red almost is like an adverb describing hot in that sentence!
3. Speaking of adverbs, when the first of the two words ends in -ly, no hyphen is needed. Observe: I am a heavily praised editor. (It's just an example sentence. I promise! 😂)
Rules for compound adjectives or nouns: