You would hardly believe how many synonyms our language has for idiots, dummies, dopes, boobs, nincompoops, and morons. (OK, OK — so maybe you would believe it….)

Since we all know — and often feel like — brainless people, I’ve been wanting to share these with my readers; and the approach of April Fools’ Day makes a fine excuse.

(For obvious reasons, I didn’t want to talk about stupidity and madness during the week right before Easter; we’ll reserve that slot for religious words in our next column.)

Instead, with its concomitant theme of madness, mid-March works nicely for a weird-words piece on various types of mental incapacity.

Here are more than a few — with thanks to the Online Etymology Dictionary:

To begin with, insane is of course just a negative of sane, which in turn derives from Latin sanus, meaning “sound, healthy.” Curiously, it is not related to the secondary sense of sound, implying “good” and “normal” (e.g, safe & sound). That alternate meaning, however, does connect to the well-known German interjection gesundheit, having to do with soundness in health.

Crazy, by contrast, is from a very old word meaning “to shatter, crush, break” — though again, somewhat surprisingly, that is not related to crack.

As for lunacy, lunatic and the related slang-term loony: Many readers know that this is tied to lunar, since it’s often assumed that the moon affects emotions and mental health. Scientifically, there is wide disagreement on this; but it does at least explain the werewolf myth. (And for the record, our word month derives from “moon”; and in this way, the menses word-group likewise connects to our glowing earthly satellite.)

The idea with lunacy is that one’s mental state is just as unstable as the ever-changing moon — and as it happens, that’s also where we get mad (and madness); it’s related to the Latin base mut-, meaning “change” (as in mutate, commute, immutable, permutation and many others.)

A personal favorite among word-study tools is my handy 1979 Roget’s International Thesaurus, which is organized not with alphabetical entries like a dictionary, but rather in broad topics — for instance, “goodness,” “warfare,” “anger” and “stability.” Each of these then branches out into dozens (or hundreds) of related terms.

While many words under “insanity” are of course medical, we do find an impressive list of slang, all ending with Y: daffy, nutty, batty, screwy, kooky, wacky, dotty, balmy — to which I might add bananas, bonkers, gaga, nuts, bats, fruity, cuckoo and (getting back to where we started) … cracked and crackers.

But the real treasure-trove in this topical Roget’s is its list for “fool,” which I herewith present in honor of the upcoming April 1 date.

(Since many of these have similar endings, keep in mind that poll and pate are very old synonyms for “head.”)

Have fun:

Dolt, dunce, clod, dullard, stupid (yes, this can be a noun), ninny, ninnyhammer, looby, noddy, witling, lamebrain, rattlebrain, peabrain, scatterbrain, harebrain (because rabbits are notoriously witless), clodpoll, clodpate, rattlepate, dunderpate, addlepate, numskull, nitwit, halfwit, thickwit, dimwit, cretin, klutz, fuddy-duddy, dotard, oaf, lubber, gawk, lummox, rube, clodhopper, juggins, tomfool, jackass, clown, buffoon, milksop, doodle, mooncalf, sap, dingbat, dingdong, ding-a-ling, jerk, ignoramus and imbecile.

Not to mention more than 30 words ending in “head”: blockhead, dumbhead, stupidhead, dullhead, bufflehead, bonehead, jughead, lunkhead, chucklehead, knucklehead, chowderhead, muttonhead, beefhead, softhead, saphead, meathead, noodlehead, pinhead, cabbagehead, pumpkin-head, fathead, blubberhead, muddlehead, puzzlehead, addlehead, tottyhead, featherhead, puddinghead, mushhead, blunderhead and dunderhead.

Yiddish has contributed schmuck and schlemiel, while British slang gives us gaby, gowk, sawney, clot, jolterhead and jobbernowl.

Those last few are classic “weird words” — along with the fan-fave flibbertigibbet, which technically means a “chattering, flighty or light-headed person” (dictionary.com).

A nit, by the way, is technically a “louse egg,” and thus a nitwit is someone whose brains are correspondingly tiny. This is also where we get nit-picky — because the eggs of lice need to be picked off the scalp with extreme care and fastidiousness.

Looking ahead to 2025, I see that next year’s April Fools’ falls on a Tuesday — same day people start receiving their Webb Weekly.

Fair warning.