"Cowardly" as an adverb [closed]

Is "cowardly" both an adjective and an adverb?

Question inspired by this awkward error message from Homebrew.

Error: Cowardly refusing to 'sudo brew install'

Surely there is another way to say so.

Of course, there are other ways to say it, such as cravenly (suggested by commenters) and timidly.

However, many dictionaries do indeed list cowardly as both an adjective and an adverb.

• Google (Oxford Dictionaries Online, as pointed out by @EdwinAshworth) (lists adverb form as archaic)
• Wiktionary (also lists adverb form as archaic)
• Dictionary.com
• Merriam Webster (curiously, this one lists the adverb form first)

We do tend to use cowardly in its adjective form (e.g. "in a cowardly manner"), and that is probably why Google claims that the adverb form is archaic. However, as you demonstrated, the adverb form is still in use in some places today (or maybe the homebrew developers are ancient people--after all, many experienced guy programmers have beards).

It seems that tacking on -ly to a noun is often used to make it an adjective, and quite often, the adjective form is also usable as an adverb. Examples include (sentences self-composed):

• daily

  The daily (adj.) schedule is posted on the board.

  I wash my clothes daily (adv.). (Aren't I a hygienic person?)

• hourly, weekly, yearly, etc.

• leisurely

  Every night, the young man takes a leisurely (adj.) stroll down the street.

  She walked into the store and leisurely (adv.) examined the array of purses on display.

• womanly

Other words typically used as adjectives but also available as adverbs (@EdwinAshworth kindly pointed out that such adverbs are known as flat adverbs) include stately, lively, deadly (this one seems a bit different than the others: "deadly pale"), likely (probable or probably), and early (this is not the typical -ly construction, as far as I'm aware). Note that, for some of the words above, Google does not list the adverb forms, but Dictionary.com does.

Exceptions exist too, such as friendly and costly.

The above lists are almost certainly incomplete, and I am sure that, as language changes, other adjectives will become adverbs, or nouns into adjectives into adverbs. At any rate, therefore, if you come buy an adjective that you'd like to use as an adverb, check it in the dictionary. If it's not there, but you really want to use it (and think it sounds right), get enough people to do the same thing, and Google might even change for you.

An interesting and perhaps more correct adverbial form of cowardly is cowardlily. This rule works for other -ly adjectives too:

And yet the busy men found time to greet him friendlily : "H'are you!"

http://www.dictionary.com/browse/friendlily