We know of many cases where hyphens are necessary to distinguish a compound word (man-eating) from a pair of separate words (man and eating). But are there any cases where a hyphenated word has a different meaning than a like-sounding, non-hyphenated word? (Note that this excludes examples like coop and co-op, because they are not homophones.)
The only possibility I can think of would be in constructs such as pro-test (meaning "in favor of tests") versus the noun protest. Any other examples, contrived or otherwise?
EDIT: A colleague of mine came up with a better one: run-down (adj.) versus rundown (n.).