: There is no way pizza-box is hyphenated.  Your example is moot. "Eight-legged" is an adjective, not a noun. In general, compound adjectives get a hyphen. I shouldn't say "never" because there are some nouns that are hyphenated, like "brother-in-law", but generally nouns are not hyphenated. That is antiquated style. The general rule is to use the open form unless there is a clear ambiguity, and I don't think the contrived "nerd lovers" example you give is one. Actually, I would argue that the hyphen conveys the meaning you are trying to avoid. "nerd-lovers" means to me nerds who are also lovers, not lovers of nerds, since "nerd" is a noun. –