Most hyphenation in compound adjectives occurs when the compound adjective comes before the noun, that is, in the attributive position. As a broad rule, when a

Most hyphenation in compound adjectives occurs when the compound adjective comes before the noun, that is, in the attributive position. As a broad rule, when a compound adjective appears after the noun it modifies, that is, in the predicative position, it will not be hyphenated. That is so arbitrary. Your source and the OP's source are linguistically prescriptive. Prescriptivism is unscientific and it leads to endless spats between groups of people that think the way they learned to speak and write is somehow superior. A better approach is to look at the reality of how native speakers of a language use, pronounce, and write words (descriptivism) and agree that some uses are standard, and some are non-standard. Here are some screenshots of collocation searches involving post-adjectival 'looking' from the excellent COCA... 'good': http://s9.postimg.org/r4cok4spb/good_looking.png http://s9.postimg.org/r4cok4spb/good_looking.png 'nice': http://s9.postimg.org/kcm9ha3pr/nice_looking.png http://s9.postimg.org/kcm9ha3pr/nice_looking.png Here's one for your author's example, "well known" (or "well-known"): http://s9.postimg.org/64wksmr0v/well_known.png http://s9.postimg.org/64wksmr0v/well_known.png Notice that the reality bears almost no resemblance to the prescriptive idea of what's correct and incorrect.