Originally Posted by dark

man eating shark can't mean the same as man-eating shark

without the use of a hyphen, in order to have the same meaning you would have to rearrange the sentence, ie. the shark was man eating

the hyphen establishes the subject of the clause as the noun "shark" and the adjective as the compound "man-eating", whereas in the absence of a hyphen there is no longer an adjective and the clause reverts back to the standard "noun-verb" structure

therefore:

man-eating shark: man-eating = adjective, shark = subject
man eating shark: man = subject, eating = verb, shark = direct objective of the verb "eating"