What’s in a dirty word when expletives are no longer deleted--even on television? Zounds!

“When my 7-year-old son asked me, ‘When were bad words invented?’ writes Linda Lee Bell of Malibu, “you immediately popped into my head. . . .”

It is not especially flattering to hear that one pops into mind at the very mention of bad words, even though Mrs. Bell explains: “I know how much you are intrigued by words and by questions like these.”

She goes on to speculate that perhaps the first bad word was spoken by a cave man when he dropped his club on a toe or stubbed a toe on the wall of his cave.

I am indeed intrigued by the origin of bad words, and I have an idea that Mrs. Bell is right in suspecting the earliest members of our species.

In those dawn days of human evolution, when man had dropped from the trees and his brain was growing, I suspect that his first words, above the level of an unintelligible grunt, were swear words.

In fact, when he stubbed his toe he may have said something very much like the four-letter word in most common use today, one invariably used to imply disgust, disbelief or dismay. Despite its universality, the word is still taboo in a family newspaper, though for some reason its French equivalent is permissible. There is something about French that lends elegance to the lowliest of expletives.

In the spirit of these liberated times, Mrs. Bell implies that the first bad word might have been spoken either by a man or a woman; but I have an idea that even in cave days women, as guardians of the children, were discouraged from using bad language, and I doubt that any cave wife would have had the temerity to use a bad word first.

I remember that only a few decades ago, when I was a youth, I lived in anxiety that some uncouth male would inadvertently utter an obscenity in front of my girlfriend.

Today, however, one not only is not embarrassed when a man uses a dirty word in the presence of the opposite sex; one is hardly embarrassed when what we used to call “a sweet young thing” uses one herself.

I used to have a male chauvinist prejudice against women using four-letter words. I thought it was unseemly. But they have proved it is one of the many things they can do as well as men, if not better.

Although I have always had the license, being a member of the privileged sex, I use four-letter words very sparingly. During World War II, I lived for months in a tent with five other Marines. One four-letter word, known to everyone who watches TV, was ubiquitous in our speech. It served every purpose--noun, verb, adjective, adverb and meaningless interjection. I actually heard one of my tent mates use the word six times in one sentence, and I’m sure that was not rare.

Naturally, one of the most difficult problems of readjustment to civilian life after the war was learning to eliminate that word from one’s language.

Through sheer discipline and a naive belief in the innocence of the home front, most of us learned it rather quickly--only to stand by dumbly as our womenfolk picked it up.

Today it is commonplace to watch a TV movie in which both of the most common four-letter words are used freely, by men and women. Not too long ago the use of such words, even in a theater, would have brought the vice squad pounding onstage to close the show.

This doesn’t really bother me. Obscene language lends verisimilitude to drama. I wonder how Ben Hecht and Charles MacArthur managed to make the language of those disreputable newspaper reporters sound authentic in “The Front Page” without the use of a single four-letter word. How would “The Front Page” play today?

Remember how Edmund Lowe and Victor McLaglen as Sgt. Quirt and Capt. Flagg burned up the screen in “What Price Glory?” with their pugnacious dialogue, delivered with snarling faces chin to chin, and without a single obscenity?

The idea seems laughable today.

Being rather irreverent, I have a tendency to use profanity rather than obscenity when I am provoked. Besides, it seems to me that if one is going to use strong language one ought to do it in defiance of the gods, as well as one’s fellow man.

Oddly, though, many fine old profanities have vanished from daily use. We may still take the Lord’s name in vain, when exasperated, but the rich profanities of the Elizabethan age have been expurgated from the language, probably as a result of Puritan restraints.

Some years ago I used the term “God’s teeth!” in this space and received two or three letters of protest. God’s teeth is just one of several Elizabethan profanities derived from a sacrilegious reference to God’s person. Others were God’s blood! which became, in later romances, ‘s blood! and God’s wounds , which was diluted to zounds!

Obscene and profane language was kept alive and vigorous in the Colonies largely by sailors, who insisted on swearing, drinking and fornicating on our puritan shores, despite the legal hazards.

It is to those drunken sailors, and to that first cave man, that we owe the common expletives of our movies and our drawing rooms.

It is doubtful that the cave man said zounds , since he would probably not have refined his religious concepts to a single godhead, but he may have invented the permissible French equivalent of our most common curse.