Writers are frequently admonished to avoid the use of clichés. (Some writers, such as Ernest Hemingway, eschew flowery descriptions and favor simple, unadorned prose.)
Non-native speakers may be confused by phrases such as “The ball’s in your court” or “It’s raining cats and dogs,” idiomatic expressions that are understood figuratively.
Some of these phrases once had a literal meaning. “Pull out all the stops,” for example, pertains to the pipe organ, which produces a louder sound when all the stops (knobs) are pulled out.
Phrases that become well known over time can be used to quickly create an effect:
“For this event, we need to pull out all the stops,” the CEO told his advisors.
A careful writer, however, will avoid overused phrases such as “Take my advice with a grain of salt.”
As phrases get passed on orally, distortions and variations frequently occur. Both butt naked and buck naked have been used to describe a person who is naked; both will likely continue to be used as slang, which is, by definition, “nonstandard.”
Most people wear clothes outside of their own households, so the sight of someone unclothed is likely to elicit remarks.
Here’s an interesting explanation for the phrase “naked as a jaybird.” (Why, one might ask, would a bird be considered “naked”?)
Stark (complete, total, absolute; bare) naked and plumb naked are other common choices. (One meaning of plumb is “absolutely”.)
If you are writing fiction, you are free to invent your own colorful phrases that fit the character or setting. For nonfiction, a descriptive adverb such as completely (or totally) naked works fine.
And if you are a minimalist writer, as Hemingway was, “naked” pretty well (un)covers it!