the Big Three of lazy, shallow, and incorrect liberal analyses of fascism are "fascism is when authoritarianism" "fascism is when you use dehumanizing language" and fascism is when someone feels disgust"
the actual coherent correct description of fascism is "a reactionary traditionalist nationalist ideology"- more specifically reactionary in the sense of trying to restore pre-liberal social forms (instead of just restoring earlier forms of liberalism) and nationalist in an exclusionary manner- (ethno-nationalist or religious-nationalist rather than civic-nationalist, seeking to strip citizens of racial or religious minorities of their equal citizenship)
this is both borne out by how self-identified fascists behave, and also by how they describe their own politics. "reactionary" "nationalist" and "traditionalist" are all terms they regularly use to describe themselves.
maybe you could narrow the definition further and say it should only refer to reactionary traditionalist nationalism that draws influence from hitler and mussolini- so for example hindutva wouldn't count- but this is a semantic quibble. whether we consider hindutva ideology to be the south asian form of fascism, or a south asian form of reactionary traditionalist nationalism which is equivalent to (but distinct from) fascism, it's just as vile either way. [EDIT: as pointed out by sivavakkiyar, hindutva ideology does take influence from hitler and mussolini, and is thus indisputably fascist. thank you to sivavakkiyar for the correction!]
but liberals naturally don't care about any of this, they just want an excuse to say "that woman on the bus told me to stop jerking off in front of her (authoritarianism!) and called me disgusting (disgust based politics!) and said I was acting like an animal! (dehumanization!) she is LITERALLY Hitler!"