Some words are strictly one-meaning words - they have one sense and they stick to it throughout the year. Other words may have several meanings from an early age and they continue with these for the duration of their lives. Both of these categories present a solid, dependable vocabulary which gives us little ground for confusion.

Other words are not so accommodating. These are the words filled with the need for change. Some of these may spend the earlier part of their working lives meaning one thing, only to undergo a major sense change late in life, leaving us - initially at least - in a state of uncertainty. Gay is a classic example of such a word.

Others again spend their whole lives in a process of evolution and change. They acquire new meanings with the years and we never quite know where we are with them. Such a word is attitude. From its very inception attitude has been a bit of a mixed-up kid. In origin it is the same word as aptitude, a word with which it now has little in common. Both came into the language ultimately from the same Latin word aptitudo but aptitude came into English reasonably directly via old French and attitude has Italian as well as French connections.

When attitude first came into English in the seventeenth century it was as rather a specialist term, being used in fine art to describe the disposition or posture of figures in paintings or statuary. But early eighteenth-century attitude had widened its remit to be used to describe the posture of the body, thought to be characteristic of some action or mental state.

Thus, someone clutching the brow might be described as adopting the attitude of a thinker - or indeed of someone who has a headache. Someone sitting with bowed head and face covered with the hands might be in an attitude of despair - or perhaps in an attitude of suppressed mirth.

Attitude at this point in the early eighteenth century was also used in dancing and the theatre to describe body posture. It soon found the necessity for having a verb to accompany it. Strike was the lucky verb and people have been striking attitudes ever since - not always on the stage, at that.

In the early nineteenth century attitude grew tired of being restricted to the body and fancied something of a more intellectual nature. Instead of confining itself to a physical posture or position it also came to mean a mental position. In this sense, attitude means the habitual way of thinking or feeling about someone or something and the resultant behaviour which follows this. Thus insular people may have a suspicious attitude towards foreigners or strangers, men may be accused of showing a sexist attitude when opening doors for women, and so on.

At this stage, attitude was more or less a neutral word. Attitudes could be good or bad, favourable or unfavourable. It has to be said, however, that people are more likely to say censoriously, ''I don't like your attitude!'', than they are to say, ''I do so admire your attitude!''. This was to prove a sign of things to come.

When someone says that he/she does not like your attitude, the attitude in question tends to be a negative, unco-operative or hostile one. Attitude's latest linguistic shift reflects this. Of course, the older, neutral meaning still exists, but attitude now, in trendy circles especially, also means truculence, according to the Concise Oxford English Dictionary.

Truculence indicates a kind of aggressive defiance and so you might well expect attitude to be a word of condemnation. Certainly, truculence is not generally held to be an admirable characteristic. However, attitude is certainly not without its admirers. We acquired the new-style attitude from the good old US of A and the American dictionary, Merriam Webster's Collegiate Dictionary, defines it thus: ''A hostile or negative state of mind'' or ''A cocky or arrogant manner''.

You can see the truth of the matter is now beginning to emerge. Hostility and negativity are not yet universally openly admired but we do not live in times when humility is likely to get you very far. Cockiness and arrogance may not sound admiral features in themselves. Rephrase these as assertiveness and chutzpah and you can see how attitude in its new sense is a word likely to appeal to these go-getting days. No wonder that it gained rapidly in currency after spreading from America in the early nineties.

New-style attitude could have been designed for the nineties. ''A highly independent or individual outlook and approach; assertiveness, style, panache'' - so the Oxford Dictionary of New Words defines it and what word could have a more appropriate accolade for this decade? This meaning of attitude exists particularly in the phrase ''with attitude''. This is often applied to people, those people who are out there in the thick of things taking both life and potential competitors by the throat and making their mark.

The phrase with attitude may also be applied to the inanimate. Restaurants, food, shows, books, humour, fashion, travel destinations . . . practically anything can be described as being with attitude so long as the trendy think that it has what they perceive to be individuality and style.

Assertiveness and liveliness, preferably slightly forced, are the constant companions of modern attitude. If you have the remotest fear that you could be classified as a shrinking violet or, worse, a trainspotter, do yourself a favour: give attitude a body swerve.

an aptitude for attitude

how attitude has been struck in The Herald recently

I'm very keen to work with the Glasgow tourist board. Eddie Friel has a very refreshing attitude to tourism

l It was the public display of this lust for lovelies, the huge envying audiences, which created the atmosphere of ''changing attitudes'' the organisers so craved

l She puts us through it, no question, uncompromising both in language and in attitude - one-liners that shriek of banality yet acquire, by repetition, a certain lurid poetry

l His attitude mirrored that of Anderson, who said: ''A draw would save us, but there is no way we can play for that''

l In order for you to manage your financial affairs more prudently, you must go back and retrieve the more innocent outlook of your childhood, get rid of the attitude towards money that developed in your youth, and learn to be more thrifty

l And, like thousands of others, I found Hemingway and he made it look easy. Mind you, I didn't share his attitude to life at all