IT IS HIGH time Miss Manners made some pronouncements on proper dress for ladies and gentlemen. The reason she has not done so before is that every time it is high time, timeschange.

Fashion is such a wily thing, making havoc of the standards of respectably stodgy people. You would suppose, for example, that Miss Manners would be quite safe in saying (head high, voice firm): A lady does not properly exhibit her nipples in the office.

No, she wouldn't. Some smart aleck with a book would come forth showing figurines of ladies from ancient Crete (going about their ancient Cretan office chores) with their necklines slightly above their waistlines; or, worse, with embarrassing photographs of contemporary ladies during that recent summer of the flowered cotton skirts and little matching T-shirts.

The sad fact is that while concepts such as decent and disgusting, tasteful and vulgar, elegant and hideous, are eternal, the specifics of them do tend to shift a bit. This annoys Miss Manners no end. What a nuisance it is to have to observe and even converse with a person to know if that is a lady or gentleman, instead of just checking out the hat and gloves.

Miss Manners has not given up her own absolute standards, you understand. There is no use creeping up on her with your wheedling questions about whether black is suitable for a wedding "these days," or white shoes in winter. No, no, a thousand times, no.

It is all she can do to remind herself that a woman who pierces her ears may possibly otherwise be a gentlewoman, and a man who exhibits the points of a handkerchief in his breast pocket may conceivably have something to say for himself.

Let us try, therefore to confine ourselves to general observations that may be safely learned and then used as a permanent measure against the fashions of any particular day.

There is a limit to the amount of lying one can do with clothing. Miss Manners understands that it is the chief function of many garments to swear that the body inside is younger or richer than it is, but anything that is off by, say, a decade or 10 percent of one's income is not going to get away with it. The definition of pretentiousness is a lie that has been detected.

There is a limit to the amount of truth-telling one can do with clothing. Dressing inappropriately for a job, social event or ceremonial occasion, on the grounds that one does not really want to be identified with the other participants, tends, when blatant, to arouse hostility in the other participants. One may do this in gradations of conservativeness or liberality on the basic costume, but anything more is a rudeness. The custom of placing one's sentiments in words across one's chest is so unspeakable, Miss Manners refuses to discuss it.

To be shocking, one must take care that the shock be properly understood. People who wear something that is so new that nobody else has ever heard of it run the risk of being thought to be the victim of inadvertent madness. It is best, if one wishes to be a fashionable leader, to be the second one on the block to adopt something new, and the first to drop it.

One does not signal general romantic availability by dressing for the stages of romantic conquest. Those who believe that people reject presents that are prettily wrapped because it is too much of a nuisance to unwrap them are in error.

If one shows up at an event in clothes from an entirely different context--sports clothes at a party, or evening clothes in the daytime--one has to go around explaining why to everyone there, which is more of a bore than changing.

Enough of these waffling generalities. Miss Manners is ready for an absolute decree:

No person wearing a safety pin through the skin can be a lady or a gentleman.

MISS MANNERS RESPONDS

Q. I thought you could enlighten me as to how to react (or how I should have reacted) to a situation that happened last night.

I went to a party with a man I'd met a couple of weeks ago. I was upstairs, talking to some people, and he was downstairs. After a while, I went downstairs to see how he was doing, and I walked in just to see him taking down a woman's phone number and telling her he was off on Mondays and Tuesdays. I stood there for a moment, not knowing what to do, and then went back upstairs. But they both knew I saw and heard what had transacted.

What I felt like doing was making a scene, grabbing the phone number, tearing it up and telling her and him to drop dead. But I played cool. When he came back upstairs, I held back nasty comments and went on to have a pleasant night. I like him a lot and was looking forward to getting to know him. But I found what he did very nervy, and it changed how I feel about him.

So my question is, how should I have reacted to catching him taking her phone number? And when I hear from him next, should I bring up the subject and state my displeasure? What do you think of a man who would do that? I would like to see him again, but if he does that kind of thing a lot, then I won't bother. I would like to let him know how I felt about him doing that when he was my date, but I guess I want to say it in a way to avoid future uncomfortable situations, and not chase him away at the same time.

A. Miss Manners is happy to tell you that you acted correctly. Tearing up the telephone number and telling the young man to drop dead probably would not have led to the goal you state of getting to know him better.

Technically, he did not commit a crime, but was the victim of an accident. The bond of datehood is not what prohibits a person from initiating a new relationship during the course of a bespoken evening. ("Go out with him anyway; you'll meet his friends," as Miss Manners' dear mother used to say.) The faux pas is courting one lady in front of another, but he did not intend to do that. Had you known that he instead telephoned the host the next day to inquire who that devastating woman was, you would not, Miss Manners dares say, have felt much better.

Let us therefore give him the benefit of the doubt, and suppose that he will take care that such an accident does not recur. The question you then face is whether you can handle a non-exclusive relationship with him until such time, if ever, as you both decide you cannot bear not belonging to each other.

And the answer (Miss Manners will kindly supply it for you) is that you must. The desire to limit another person's social freedom is never attractive, and is tolerated only when that person has a desire opposite in direction and equal in intensity. A premature desire of this kind is a disaster. Or rather, as Miss Manners knows perfectly well that we would all like to be able to cherish complete freedom while binding others to strict fidelity, the expression of such a desire is a disaster.

Q. I am a divorced woman who has no nieces or nephews on my side of the family. There are nieces and nephews on my ex-husband's side. Am I still considered an aunt?

A. It is said that one cannot choose one's relatives, but the fact is that you can. You are an aunt if you want to be one.