George Orwell, here:
It will be seen that, as used, the word ‘Fascism’ is almost entirely meaningless. In conversation, of course, it is used even more wildly than in print. I have heard it applied to farmers, shopkeepers, Social Credit, corporal punishment, fox-hunting, bull-fighting, the 1922 Committee, the 1941 Committee, Kipling, Gandhi, Chiang Kai-Shek, homosexuality, Priestley's broadcasts, Youth Hostels, astrology, women, dogs and I do not know what else.
Yet underneath all this mess there does lie a kind of buried meaning. To begin with, it is clear that there are very great differences, some of them easy to point out and not easy to explain away, between the rĂ©gimes called Fascist and those called democratic. Secondly, if ‘Fascist’ means ‘in sympathy with Hitler’, some of the accusations I have listed above are obviously very much more justified than others. Thirdly, even the people who recklessly fling the word ‘Fascist’ in every direction attach at any rate an emotional significance to it. By ‘Fascism’ they mean, roughly speaking, something cruel, unscrupulous, arrogant, obscurantist, anti-liberal and anti-working-class. Except for the relatively small number of Fascist sympathizers, almost any English person would accept ‘bully’ as a synonym for ‘Fascist’. That is about as near to a definition as this much-abused word has come.
But Fascism is also a political and economic system. Why, then, cannot we have a clear and generally accepted definition of it? Alas! we shall not get one — not yet, anyway. To say why would take too long, but basically it is because it is impossible to define Fascism satisfactorily without making admissions which neither the Fascists themselves, nor the Conservatives, nor Socialists of any colour, are willing to make. All one can do for the moment is to use the word with a certain amount of circumspection and not, as is usually done, degrade it to the level of a swearword.