“Immovable object” as a career choice.

Dear Word Detective: My girlfriend often complains about her adult brother “sponging” off their parents — living in their basement, not having a job, etc. For some reason yesterday, I suddenly realized that “sponge” is a pretty strange word for “acting like a parasite.” What’s the story? Sponges always struck me as pretty self-sufficient, if boring, things. I’m not even sure whether they’re animals or plants. Are there such things as vampire sponges that play computer games all night and depend on other, more industrious, sea creatures for support? — Name withheld by request.

Vampire sponges, perhaps wearing little black capes, turning themselves into sea-bats? Sure, go ahead and laugh. People thought tomatoes were pretty harmless until that documentary “Attack of the Killer Tomatoes” came out (“I know I’m gonna miss her; a tomato ate my sister”).

According to Wikipedia (caveat lector, yadda yadda), “Sponges are the simplest animal,” being essentially just a collection of cells. They lack a nervous system and any internal organs, and basically spend their lives hanging out in one place and waiting for food to float by. I’d say that’s probably a pretty good description of your girlfriend’s brother, but it also applies to Wall Street, so we should probably “drill down” a bit, as the frackers say, for a more precise understanding of the metaphor.

What we call a “sponge” in the “please wash my back” sense is actually the skeleton of the critter, the soft, flexible perforated framework it leaves behind when it finally decides to “throw in the sponge” and move to Florida or whatever. Sponges (often called “sea sponges” to differentiate them from their synthetic rubber or cellulose imitations) are actually farmed today, though the bulk of the world’s sea sponges are still “caught” by sponge fishers.

Sponges have been used for centuries, primarily as an aid to bathing or cleaning. (The expression “throw in the sponge,” meaning “to abandon an effort,” comes from prizefighting, where the sponge used to cleanse a fighter’s face between rounds was thrown into the ring to signal that he was quitting the fight. “Throw in the towel” is the more common form today.) The word “sponge” itself, which first appeared in Old English, comes from the Greek name for the animal, “spongos.”

What makes the sponge useful is, of course, its ability to soak up and hold a large quantity of water (far more than a washcloth or towel), which makes it handy for both washing things and cleaning up spilled liquids (“The spunge is ful of water, yet is it not seene,” 1580). This magical ability led, in the 14th century, to the appearance of “sponge” as an English verb meaning “to wipe with a sponge” as a means of cleaning. Various figurative uses of the verb followed, the most notable being, in the 17th century, “to sponge” meaning “to drain or empty,” by analogy to squeezing a sponge. This gave us “sponge” meaning to “squeeze” or pressure a person for money or favors (“Yea, taking the clothes off the people’s very backs, … and always spunged them for money,” 1716). By the 18th century, this “sponge” had broadened to signify an entire “lifestyle” of living off the labor of others as a parasite (“They will cheat the public at their shops, or sponge on their friends at their houses,” 1857). And that explains what your girlfriend’s brother does for a living.

Incidentally, the word “parasite” is actually far more interesting and rewarding than the sort of person to whom it is usually applied. It comes from the Greek “parasitos,” meaning a person who sits at the table (“para,” beside) of another person and eats their food (“sitos,” food). The word was used in Ancient Greece to mean a professional dinner guest, one who survives by amusing and flattering the rich.

Case closed.

Dear Word Detective: I am wondering how the phrase “for good” came to mean “forever,” as in “He finally quit smoking for good.” There may be some interesting philosophical roots to this idiom. — Josiah Kollmeyer.

Perhaps. But probably not. Generally speaking, the English language is random, resistant to logic, and contemptuous of continuity to a degree that seems almost willfully perverse. Sometimes, in fact, the whole shebang makes a million monkeys with typewriters look like a good plan for imposing some coherence, provided we can wean them from writing scripts for HBO. Don’t mind me; I get this way in election years. But have you noticed that almost every prime time TV show in the US at the moment involves super psychic cops and serial killers? This does not seem like the harbinger of a new Age of Aquarius, to put it mildly.

Meanwhile, back at your question, that’s a darn good one, using “good” in one of its common adjectival senses of “sound, cogent, fit, suitable, appropriate.” The adjective and adverb forms of “good” have a whole herd of other meanings too, most of which connote a positive sense of the thing or action that they describe. There is also, of course, the noun “good,” which can mean anything from the abstract sense of “something positive” to “something produced for sale” (usually in the plural “goods”). “Good,” in other words, comes with a lot of wiggle room, which is “good” because it makes “good” a very useful word. But it also sometimes makes “good” a mysterious and maddeningly vague one.

“Good” first appeared in Old English as “god” (with a long “o,” meaning that it sounded like “goad”). The source of our “good,” and similar forms in German, Swedish, etc., was the Proto-Germanic root “godo,” which may be a variant of the root “gad,” meaning “to bring together, to unite,” also giving us the English verb “gather.” The earliest sense of our adjective “good” was simply “suitable, fitting, appropriate.” Our “good” lacks the expected comparative and superlative forms (which would be “gooder” and “goodest”); instead we use “better” and “best.” The adverb in English corresponding to our adjective “good” is, of course, “well.”

Most of the senses developed by “good” over the centuries have carried a connotation of the thing, action, person, etc., being satisfactory, appropriate or sufficient. What’s “good” is good, not wonderful or fantastic, but solidly OK. That sense of “sufficient” has given us the use of “good” in “good for,” with either a task or a time appended, as in “These batteries are good for twelve hours” or “That mower is only good for small lawns.” We also use “good” to mean “a considerable amount” (“It’s a good ways to the next gas station”) and to mean “at least” (“He walked a good ten miles every day”). This sense of “substantial” also underlies the intensifying phrase “good and” (“Bob was good and drunk after his eighth beer”).

It’s this sense of “completeness” that gives us the phrase “for good” meaning “finally” or “forever.” When something is settled “for good,” the result may not be “good” in the sense of “positive or desirable,” but it’s definitely over (“After Lyle’s third arrest for mopery, Karen moved out for good”). The original form of the phrase, when it first appeared in the early 16th century, was, in fact, “for good and all,” which is an even more emphatic way to say “it’s over” (“He was obliged for good and all to leave his country,” Thomas Boston, circa 1732).