I have a bad habit (for an American) of looking things up in the OED first and not checking to see if Merriam-Webster agrees.
Sometimes this habit results in my changing a spelling that’s acceptable in U.S. usage or hyphenating a word that M-W doesn’t.
When I recently encountered online examples of the unhyphenated words unAmerican and copayment, I consulted both dictionaries to see if I had fallen behind the times.
Both OED and M-W show co-payment and un-American as the only options. Even the AP Stylebook allows a hyphen in un-American.
Perhaps online journalists and merchants who do not hyphenate these words are using other style guides. Or maybe they just don’t care.
Here are some examples that indicate that not everyone thinks that words like co-pay, co-payment, co-insurance and un-American require hyphens or even that adjectives from proper nouns require a capital.
Copayments and Other Information (Wisconsin information site)
What’s the difference between copays and coinsurance? (Quicken app FAQ)
The member only pays their copayment for any additional admissions (Blue Cross information site)
“UnAmerican Graffiti” (episode title, NYPD Blue)
“Unamerican” (song title on Cletus Got Shot album)
Unamerican (section title, Huffington Post)
My email to my unAmerican Representative (headline, Daily Kos)
Knowing when to hyphenate nouns formed with common prefixes like co- and un- can be tricky, even when consulting a dictionary or stylebook. For example, M-W hyphenates co-pay, but not coeditor. CMOS (Chicago Manual of Style) goes with coeditor, but opts for co-opt. Both OED and AP give the nod to co-editor, and every one of the sources I use acknowledges the spelling un-American.
I find myself wanting to pick and choose according to my own feelings about the way a word looks.
Because I don’t like the look of coeditor and coauthor, I want to go with AP’s “Retain the hyphen when forming nouns, adjectives and verbs that indicate occupation or status.” But although AP includes co-author, co-pilot and co-star in the “occupation-status” category, they relegate coed to their unhyphenated list. If I want to write co-ed, I have to turn to M-W for justification.
Professional writers don’t have the option of this kind of mixing and matching. Publishers, on the other hand, do.
Some publishers and organizations compile their own” house style guides,” usually based on one of the standard guides, but altered in some respects. For example, the AP Stylebook recommends using the country name Myanmar. For political reasons, a publisher might supersede that rule, requiring his writers to refer to the country by its former name, Burma.
In the absence of a house guide, writers whose employer has adopted a particular style guide are bound to follow it, regardless of personal preference. Freelance writers, who are their own employers, should adopt a guide for themselves to follow.