Identifying Compound words in Modern English

At least one highly regarded authoritative source, CGEL, would say that etymology is not a reliable guide to whether a word should be considered a compound one or not. Here is the relevant segment (p. 1627); the relevant paragraph is the second one, but I include the first one for context.

Morphological analysability vs etymology

Words are most clearly analysable into constituent parts when the latter occur with the same or similar meaning elsewhere, as with bed·​room, un·​kind, soft·​ness, etc. But this is by no means a necessary condition for analysability. There is no difficulty in recognising straw·​berry and draw·​ing·​room as compounds even though the meaning of the whole is not predictable from the meanings of the component bases: it is enough that the second base is formally and semantically identifiable with the berry and room that occur as separate words or in semantically more transparent compounds like black·​berry and bed·​room. Similarly with derivative bases like dur·​able and the others listed in [2ii], event hough affixes characteristically have less specific meanings than bases. There are even cases where neither component contributes a clearly separable component of meaning to the whole. The meaning of black·​mail, for example, is not predictable from the meanings of black and mail as independent words, but black remains easily recognisable as a separate morphological unit because it occurs in a considerable number of compounds and phrases where it likewise does not have its literal meaning: blackleg, blacklist, blacksmith, black magic, black mark, black market, black spot, and so on.

The case of blackmail is to be distinguished from that of blackguard. Blackmail is morphologically analysable but semantically opaque as a result of historical change. (The original meaning of the mail component was "coin, rent" and with black having the meaning "illicit" still seen in black market: the compound was interpretable as "illicit money".) But with blackguard historical change has resulted in the loss of /k/ from black, and /blæɡɑːd/ is now a simple base, not a compound: the first syllable is neither phonologically nor semantically identifiable with /blæk/. The original base black is retained in the spelling, but this can be seen as a reflection of the historical source rather than as a justification for treating blackguard as a compound. Compare, similarly, /kʌbəd/ cupboard, /ˈbrɛkfəst/ breakfast, and so on. With husband even the orthography gives no indication of the original compounding of house and bonda "householder", a word which has now vanished from the language. Any analysis of such words as blackguard, cupboard, breakfast, husband, and the like belongs therefore to the field of etymology, the study of the historical source of words, not to the field of morphology, the study of the grammatical structure of words. There is nothing in the present-day language system to motivate an analysis of such words into smaller morphological units.

Q1. If we adopt CGEL's criteria, it would seem that shepherd would not be considered as having a compound base.

Q2. Setting aside compound bases for a moment, let's first note that, in general, the base need not be a separate word in a dictionary. A base that can stand on its own is called free; otherwise it's bound. (CGEL, p. 1625). Some examples of English words with bound bases are dur·​able, dur·​ation, aggress·​ive, pre·​empt, and dis·​perse.

Getting back to compounds, there doesn't seem to be any rule of English morphology that would prohibit compounds consisting of more than one bound base. They are likely to be quite rare, but I would suggest regi·cide as an example.

Relevant (from A.Word.A.Day):

This week’s guest wordsmith Janet Rizvi (janetrizvi at gmail.com) writes:

Anu is fond of tosspot words, also words made of combining forms. But I don’t think he’s featured a week of what I’d call double-noun words. Perhaps it would be fun to consider what happens when two nouns run together to make a new concept.

In his theme of words relating to space, Anu used light-year and moon shot. I would probably have written “light year” and “moonshot”. Is either of us wrong, or right?

German is unapologetic about stringing words together without hyphens to express a complex idea; either snappy two-item numbers like Zeitgeist and Schadenfreude, or stretching to the horizon like Vierwaldstätterseedampfschiffgesellschaft (Lake Lucerne Steamship Company), spotted by my mother 90 years ago and never forgotten.

English, by contrast, rarely amalgamates more than two words. And there doesn’t seem to be any rule for hyphenating or not hyphenating compound words, or leaving them separate. Seems a bit arbitrary, depending on the mindset (mind-set?) of the writer. Even The Chicago Manual of Style, the writer’s bible, doesn’t give clear guidance.

You could theorize that when a combination of two nouns becomes common currency, initially the words are simply juxtaposed (master class, income tax), gradually a hyphen insinuates itself (light-year, water-closet), and as the compound word becomes more and more familiar the hyphen is dropped (steamship, masthead).

Finally, the two words bond so closely that it’s an effort to recall that they were ever separate (shepherd, rainbow). You could also theorize that longer words tend to remain separate. “Class distinction” has been around for a long time without the words joining together; and conversely, “witchcraft” contradicts the possible theory that an unwieldy cluster of consonants might be an obstacle to words welding together.

Still, I can discern no hard and fast rule; and I’ve noticed that double-noun words coined to meet the needs of the digital age tend to skip straight to the last stage of the process I’ve theorized, with no separation and no hyphen (photoshop, website).

These are all double nouns used as nouns, as “you need to work on your anger management”. But I think when you use them as adjectives, the separated ones do need a hyphen: I for one would certainly go for an anger-management course, or complete my income-tax return. So for this week, I offer five double-noun words, with or without hyphens, run together or separate, as I would present them. See if you agree or not.