Defining fascism is a needlessly difficult exercise. One of George Orwell's essays attempts this, explaining that the practical and philosophical differences between the fascist regimes of the time confused the issue. That most people would readily accept "bully" as a synonym for "fascist" makes it harder still. He went on to say:
It will be seen that, as used, the word ‘Fascism’ is almost entirely
That was true in 1944, and is still true today. Both Bush Jr. and Obama were often referred to as "fascist" by their opponents, further making a mockery of any attempt to use the term meaningfully.
However, here is a link which cites various academics who have published books on the matter. It is worth reading but I shall point out the core ideas and elaborate upon them.
Professor Michael Mann defined fascism's core beliefs: The transcendence of the people and state into one, which cleanses itself of dissent and diversity by force. The fascist view is that the state is not a means to an end; it is the end. Fascists also believe that their nation is superior, and this can be demonstrated by the use of force against its enemies.
RJB Bosworth defined fascism based on what Mussolini said. This is important since Italy was the first fascist regime. Mussolini should not be considered the absolute source of all things fascism; because he wasn't, but he's a good start.
To be still more succinct, as Mussolini told Franco in October 1936,
what the Spaniard should aim at was a regime that was simultaneously
‘authoritarian’, ‘social’, and ‘popular’. That amalgam, the Duce
advised, was the basis of universal fascism.
Fascism is far more of a unique ideology than many think. Some of these oddities have been summarised by Stanley Payne. Fascists are against individuality; the expression of liberty, and view individuals only in relation to their people.
What's more, fascism regards violence as a moral imperative; which is distinct from other ideologies which accept the use of violence as a means to an end, but do not promote violence in itself as morally good. This is tied to their belief in the necessity of revolutionary rebirth, which is to say that there must be a revolution; because only the strong who can seize power should rule (fascists are anti-democratic).
This belief in national rebirth also opposes tradition; which attempts to return to an imagined past, and should not be confused with fascist veneration of their culture. Fascists want to completely recreate the state and its people in their image; they are radically anti-tradition.
In addition to being anti-liberal and anti-conservative, fascism is opposed to socialism, trade unions, and communism especially. Partly because of the fascist rejection of class conflict, and also because of their rejection of the premise that all people are equal. This is why it is referred to as "third way" politics; neither first (liberal-conservative) nor second (socialist-communist).
Some fascists are often conflated with conservatives; like Franco, and there is a legitimate academic question of whether Franco and the Falangists were quintessentially fascist, owing to their alliance with the aristocracy and church. Nonetheless fascism, like any other thing, can't be defined by its exceptions. So to conclude: fascism is unique and cannot be confused with nationalism per se, it is anti-conservative and so cannot be defined as traditional or religious. Fascism is generally radical and secular.