In one word: collectivism.

The idea that "common good" prevails over individual rights.

IIRC, the word fascism comes from Latin, and means something like a bunch (as in "a bunch of sticks) and refers to an old roman military story: if you grab just one stick, you can break it really easy. But if you take a bunch of sticks, you can't break them. Therefore we should always think about the collective instead of individuals.

As Mussolini himself puts it " If the 19th century was the century of the individual, the 20th century will be the century of the collective".