My friend Olivia doesn't approve of my behaviour. She thinks I'm a slut. Her word, not mine. The cause of her reproach is the fact that during my recent trip to South Africa I had sex with an ex-boyfriend. Not just any ex, mind, one of the big ones. Not the wisest thing to do, granted, given the possibility of emotional fallout, but seeing as we we're both single, hardly a crime.

"What were you hoping for?" she asked me.
"Nothing," I said. "He lives in South Africa, I live in Ireland. That's a pretty hopeless situation as far as I can see."
"Then why bother?"
"Pleasure, intimacy, connection. Does sex have to have a point other than sex?"
For Olivia the answer is yes. As far as she is concerned sex should be used in service of an end goal – to gain love or cement a relationship – otherwise it is both immoral and a waste of time.
In many ways it's strange that Olivia and I are as close as we are since our beliefs are so diametrically opposed. Not just about sex, about everything. She believes in the Bible and in astrology, pretty much antithetical beliefs in my mind, but as Walt Whitman noted a person can contain multitudes. She also believes in waiting for the "One' and so she frowns on my choices.
"What about that guy you were seeing?" she asked.
"That's over."
"Why?"
"It was a fling, now it's been flung."
She shot me a disapproving look. "So you were just using him?"
"I doubt he'd see it that way," I said, but the thing about Olivia is, she always makes me feel that I have to justify my behaviour.
Yes, my motivation had been largely sexual, at least initially, as I'd known from the get-go that the relationship, for want of a better word, had no real chance of blossoming into a great romance – if I have commitment issues, he has commitment allergies. I enjoyed his company, he was interesting, amusing, good-natured, considerate, and he made me laugh. When the time came to part, we did so without rancour or regrets.
I explained this to her and that's when she hit me with the s-bomb.
"Don't you think you're acting like a bit of a slut?"
I've always been fascinated by the word "slut' and they way people bandy it around to pass judgement on other's sexual behaviour. What exactly is a "slut' anyway?
The Merriam-Webster dictionary defines "slut' as "a promiscuous woman'; the Online Oxford agrees, but goes further when it says that a slut is "a slovenly or promiscuous woman'; the Cambridge Advanced Learner's reckons a slut is a "sexually active woman', which surely includes married women and those in long-term relationships.
The problem with language is that it's slippery. One answer merely creates another question: if a slut is a promiscuous woman, how many people would you have to sex with in order to be considered promiscuous? Five, ten, twenty, perhaps one hundred, more?
When Alfred Kinsey did his groundbreaking survey in the late 1940s and early 1950s, he found that just one percent of women had had more than twenty lovers, and that one percent of his male respondents had had more than one hundred.
What's surprising is that things haven't changed all that much, at least if the statistics are to be believed. We are told we live in a sexually permissive society characterised by one-night stands and casual hook-ups. But surveys don't bear this out.
Perhaps then a sexually promiscuous person can be defined as anyone who has had more lovers than average. Globally heterosexual men and women are said to average thirteen and seven sexual partners respectively, but trying to decide exactly what's average is impossible, as the numbers seem to change with every survey.
In Victorian England, a woman could be diagnosed as a nymphomaniac and committed to an asylum if she had an illegitimate child, was the victim of rape or was overly flirtatious. Closer to home, thousands of Irish women were committed to Magdalene Laundries, generally for the great sin of having a child outside of marriage.
We regard these attitudes as shocking or ridiculous, forgetting that like the Victorians or the Magdelene Sisters, our own understanding of what constitutes promiscuity is no better than theirs. In fact, it's probably worse or at least harder to pinpoint since the modern, secular world rarely deals in moral absolutes.
What's promiscuity? The short answer is, it depends – it depends on our age, culture, religious beliefs, personal experience, peer groups, even our careers and education. Terms like "slut' or "promiscuous' mean something different to me than they would to Olivia or to each of you reading this column. The substance of the word depends on the person making the accusation.
More importantly, as long as you are not spreading disease or heartbreak, is promiscuity such a bad thing anyway?
The French courtesan Ninon de l'Enclos could presumably be regarded as promiscuous – she was rumoured to have had several thousand lovers. Far from being shunned from polite society, De l'Enclos was much admired for her beauty, wit and intelligence; she was an early supporter of the great French comic playwright Molière and left money in her will for her accountant's son to buy books. The boy, François Marie Arouet, later found fame as the writer and philosopher Voltaire. If that's promiscuity, we need more of it.
A more modern example is Brooke Magnanti, who in 2009 came forward as the woman behind Belle de Jour, the memoirs describing life as a high-class London call girl. Magnanti has refused to enumerate exactly how many men she has bedded, claiming that it's somewhere between "dozens and hundreds." Her experience of prostitution is presumably very different from the thousands of women forced into it, but does her past invalidate Magnanti as someone worthy of respect? I don't think so, nor do her colleagues at Bristol University, where she works as a research associate in developmental neuro-toxicology and cancer epidemiology.
De l'Enclos and Magnanti are extreme examples since they were both in the sex-for-sale business. Chances are, most of us have had far less sexual partners, even the sluts among us. Unlike both these women, who are both fascinating in their own ways, sluts have sex for a variety of reasons, but not for money.
Anyone who has read this column will know that I have absolutely no moral problem with casual sexual relationships; what may surprise you is that there plenty of occasions where I think having sex is wrong – not morally wrong, but destructive and unhealthy.
It's easy to condemn someone for having casual sexual relationships, but to my mind that's intellectually lazy as well as prejudiced. A far more interesting question is why people have casual sex, particularly women, since society has always been far more tolerant of male promiscuity.
Women may have casual sex because they want to fit in with their peer group; because they are looking for validation from men; because they want men to like them; because they don't know how to say no; because they are drunk or on drugs and don't know what they are doing; because they believe nobody will want them for more than one night; because they have no self-respect; because they are depressed, sad or lonely.
Depending on your perspective, that's slutty behaviour. But it shouldn't be condemned – at worst it should be pitied.
Women can also have casual sex because they enjoy it; because they can feel passion without being in love; because they see something attractive, mysterious or inviting in their partners; because they are revelling in their sensuality; because being erotic is part of being human and alive; because sex is wonderful, pleasurable and delightful.
That may be slutty behaviour too. And it shouldn't be condemned either. No – it should be celebrated.