This recurring “Weird Words” column aims to unpack oddball vocab like pogonip, putz, gleet, dik-dik and boustrophedon.

But you can’t just keep trotting out such lists over and over, say 138 times in a row — which is where we’re at after more than three years.

So every now and then, we dip into some other word-related topic: spelling, pronunciation, dictionaries, grammar — and of course, etymology, which studies where a word comes from, and how it’s changed over the years.

That’s what we’re looking at just now, with a somewhat obscure phenomenon called folk etymology.

As we saw last week, this is a process in which a strange word evolves into something both similar and more familiar — leading folks to assume an etymological connection, even though there isn’t one.

Take crayfish, for instance: That used to be crevis, from the German krebis, meaning “crab.” But it’s such an odd term that speakers gradually changed the pronunciation so it would sound like what it meant (an underwater creature). In other words: etymology by … folks.

Our previous installment also covered belfry (which doesn’t come from “bell”), andirons (not from “iron”) and female (not a suffixed form of “male”).

Here are more:

Hangnail, that vexing flap of skin on your finger, is not related to either hang or fingernail. Instead, the first syllable was originally ang-, meaning “painful,” while the latter referred to the type of nail you hammer — due to the way the fingernail’s shape resembles a nail-head.

And headlong does not come from long, but rather -ling, a now-obsolete suffix meaning “in that direction or manner.” (This suffix has other unrelated meanings that we do still use — as in earthling and duckling.) The “direction” sense of -ling was also found in sideling, which likewise changed into the more familiar-sounding sidelong.

Perhaps the weirdest instance in this week’s list is cockroach, which was Anglicized from the Spanish cucaracha (yes, like the famous Spanish folk song). English speakers somehow adapted this to sound like the better-known cock (chicken) and roach (a type of fish). Hmmm. If you know that the water-going type of roach includes minnows, you can see some similarity there; but where the chicken came from, I don’t know. Maybe it was crossing the road?

Penthouse, as you may now be guessing, is not connected to house, but is a reformulation of the Middle English pentis, which in turn is related to append and appendix — in the sense of something extra added on.

Meanwhile, you may have noticed that sacrilegious is not spelled like religion — because it doesn’t actually contain that word. In fact, it combines two other Latin roots: sacr-, meaning “sacred,” and legere, meaning “to steal”; it originally had to do with plundering temples or graves.

Shame-faced, likewise, is not from face, but was initially shamefast; it employed the suffix -fast, meaning “firmly fixed” (as in steadfast). I guess in this case, the shame felt particularly tough to get rid of….

Along the same lines, sovereign seems like it came from reign, since both terms have to do with primary oversight; but in truth, our English word derives from the Old French soverain (with no G); it’s ultimately related to the common Latin prefix super (as in “over” or “above”).

One you may not have heard is sparrowgrass, a slang term for asparagus. Of course, it’s just a folk pronunciation, since that vegetable is certainly not a type of grass (though for some of us, it doesn’t really taste much better).

And finally: Surround is linguistically unrelated to round (as in “all around”). The rare Latin base und- means “wave” (as in “undulate”); and if you again add “super,” you get something like “water all over” — which would certainly surround you! (Apparently, the P in “super” dropped out at some point.)

That’s all, folks — for folk etymology, anyway. This column owes a debt to the terrific Merriam-Webster website, as well as Wikipedia and a grand old text called English Words from Greek and Latin Elements.

See you here again soon.