It gets confused with 'secret', more often than not, and is invoked to stop other people knowing things about you which you'd rather they didn't.
Hence its use by guilty parties to try to stop potential newspaper stories involving affairs, drug habits, sexual peccadilloes, finances, taxes, corrupt business deals and crimes the police haven't found out about yet.
Agents, publicists, lawyers and spokesmen of every sort and stripe will squawk "PRIVATE!" down the phone at journalists most days, when the word they should be using is 'personal'.
The trouble from their point of view is that 'personal' doesn't strike fear into any hack's heart in quite the same way as 'private', which carries with it the implied threat of punitive legal action and an almost-definite bollocking from someone.
The trouble with 'private' though is that it does not actually mean those things. The word means, instead, that something belongs to you or affects only you.
So your garden is private. Your masturbatory habits are private. But if you choose to combine the two your neighbours may feel that it affects them and then the police, and if it is newsworthy in some way journalists as well, will want to get involved.
We all feel our sex lives are private, but if our partners feel our conduct has not been up to par in some respect they have a right to speak about their own sex lives, and the bit which involves you.
Those who abuse drugs may feel it's their personal choice but families, friends, the police and criminal justice system think there's a lot of other people affected by it too and again they may want to express an opinion.
Such is life; we all like to keep things private unless we feel we might benefit from sharing. Hence the kiss-and-tell. When this Fleet Street staple makes a comeback please don't think less of people for taking a cheque to bare their hearts. Would you do it for free?
Before Leveson and phone-hacking there was a greater scandal gripping the Press and that was privacy injunctions. I've written before about who and what they were about so won't repeat myself here except to say some were reasonable but most were an appalling abuse of statute.
The vague law they were based on - 17 words in the Human Rights Act - was about protecting people's rights about things that belonged to them or affected only them. Instead it was used in many cases to get an injunction about things which might affect the money in rich people's pockets, and were therefore worth the £50,000 lawyers charged for saving their blushes.
Some injunctions were broken or lifted, and after Ryan Giggs, Jeremy Clarkson and Andrew Marr failed to lose any money as a result the celebrity taste for running to a costly law firm waned.
But one or two people were still silly enough to think bending the law to suit their purposes was a good use of time and cash. Which brings me to Caroline Spelman, the millionairess Secretary of State for the Environment.
Informed that her son Jonny, 17, a schoolboy rugby star who had played for England's youth team, was about to be exposed as a drugs cheat by the Daily Fnar Funday, she got a privacy injunction banning publication.
The judge, his hands burned by previous gags which were later found to be flawed, refused to make the order anonymous and therefore everyone knew the story was about Ms Spelman's son, that he was a rugby player, and a guessing game ensued about whether it was to do with sex or drugs.
A few weeks later we all knew which, because the paper won a subsequent hearing and published its story about this young man who had represented his country and was taking banned substances including anabolic steroids and a growth hormone following an injury.
That's not private. It's not even got a shot at being private. It's illegal to import such potions, which he did by buying them over the internet, it's against the rules of his sport to take them, and the people he paid for them were almost certainly criminals.
As a result of that story this lad has been punished by being banned from playing rugby for 21 months by the Rugby Football Union. As he should be, and I'm sure getting the police involved would be overkill.
Despite already spunking £61,000 on shirking responsibility, the Spelmans are funding an appeal which may reduce the length of the ban. But the fact remains - this was never private. It was instead about a Government minister attempting to force an illegal gag on the Press in order to protect a criminal family member.
That is utterly disgraceful behaviour from a public servant in a free country. It's what you'd expect in corrupt states run by despots, the sort of place with lottery scams and home-brewed petrol.
Ms Spelman will presumably cry motherhood as a defence and say she did it to prevent the attention that publication would have brought her son and the damage it would cause his career. That, had it been granted, it would also have spared her the same attention was merely a beneficial side-effect.
The fact is that most mothers in that situation would tell their son to face the consequences of his actions, whatever they may be, in the hope he would learn not to repeat his mistakes.
That basic process is the root of morality, the idea that if you go wrong you will be punished in some way is the main thing which keeps all of us on the straight and narrow.
But then, we're expected to be good, pay our taxes and keep our heads down, while the people in charge plough their own furrow which they can make as wonky and wiggly as they please without the barest hint of shame or disgrace.
Jonny Spelman's been punished enough.
His mother should be sacked.
But I expect she'd like to kill some badgers and sell off the forests first.