With the exception of the quasi-divine Fowler, most of those who set out to instruct others in the sound usage of English end up using it rather poorly themselves, a cautionary lesson that long ago taught me to avoid the practice.

My general rule is to blush for my own lapses and call no one else to book for his. But there are words that have a precise technical significance, and whenever the misemployment of any one of them multiplies too abundantly, the ear rings with a summons to the duty of reproof.

''Mugger'' is one such word of art. Its origin lodges back in the early history of New York's Lower East Side and in Jacob Shapiro, one of that precinct's primal figures. Shapiro made his leap from apprentice to journeyman thug by steady application of the technique of approaching an elderly passer-by from the rear, crooking his arm under the throat and saying ''Gurrah,'' a signal pregnant with enough terror to empty the poor old soul's pockets all but automatically.

Shapiro christened his device ''mugging,'' and his pride in his precocity as inventor was so enduring that he preferred to be addressed as ''Gurrah'' even after his scope had widened to swell him to executive capacities under Louis Lepke, the ineffably distinguished chairman of the board of Murder Inc. Tradition has its deservings; a ''mugger'' is either Jacob (Gurrah) Shapiro or any robber-by-force who adheres precisely to his technique. A purse snatcher is not a mugger, and we are recreant in the respect owed a craft when we speak of him as one.

''Scab'' is another word of exact import. Mark Gastineau, the decreasingly precipitate pass rusher of the New York Jets, has crossed his teammates' picket line. He is being too commonly referred to as a ''scab.'' A scab is a casual laborer who takes a striker's job. A striker who quits the line and goes back to his job is a fink. It is not my business to derogate Gastineau's conduct, but anyone otherwise inclined ought to speak of it not as scabbing but as finking.

This distinction happens to be especially important to those still misapprehending enough to think their own rudimentary intelligence a match for the subtleties and sinuosities of the brains that draw up the football odds cards.

Once the season begins again, every bettor will be shrewd -- none can ever be called wise -- to factor each team's Fink Quotient (FQ) into his calculations of its future. There is every likelihood that finkery will be a roaring flood in a week or so, but last week, when it was but a trickle, was the most rewarding time for careful attention by students properly appreciative of the FQ factor.

Both the New Orleans Saints and the Tampa Bay Buccaneers had given marked evidence of improvement in the first two games. But last week, eight members of the New Orleans defensive platoon crossed the picket line. Fink Quotient 8: to be bet against from here on in. On the other hand, Tampa Bay's Fink Quotient held at zero through Friday morning, and it must therefore be treated with respect in future dealings with one's bookie.

The New York Giants started lamentably and the New York Jets triumphantly. But the Jets had reached a Fink Quotient of 5 by Friday, and if it mounts at all, they can safely be written off. The Giants, however, were still at FQ Zero, which rates them with the Bears and the Redskins and indicates that, however little they have looked it so far, they still belong with the solid teams. The Cowboys' habit of running down at the end of the season is at last explained by their Fink Quotient of 7.

No system is perfect. There are always intangibles. The Los Angeles Raiders closed the week at FQ 5 and rising, but they may have learned disdain for class solidarity from Al Davis, their owner, which would make their prospects less dismal than their Fink Quotient would suggest.

But the FQ is otherwise sound because it rests upon the most ancient of history's principles. Humanity divides into two categories: those who own property and those who work for a living. They have responsibilities to mutual courtesy, but they have nothing else in common.

In times of trouble, one stands with one's mates. There aren't many blunders with consequences more lasting than to cross a picket line when someone you have worked with every day is standing there. It is malignant to hate anyone who has finked on you, and it is folly ever to trust him again. The team is either his or yours, but it cannot belong to both of you for a long while afterward.

Before long, one of the squads that had held to FQ Zero up until then will down its picket signs and march in a body back to work. When that happens, two responses are to be advised: the first is to bow the head in sorrow, and the second is to make haste to the Las Vegas board to check that team's odds for the Super Bowl. It will have exhibited the wisdom of fraternity. No collective endeavor is a remotely secure gamble unless all its elements have the common sense to keep themselves united as one in losing or in winning.