rashness

The quality or state of being rash.

We offend . . . by rashness, which is an affirming or denying, before we have sufficiently informed ourselves.

Syn. -- Temerity; foolhardiness; precipitancy; precipitation; hastiness; indiscretion; heedlessness; inconsideration; carelessness. See Temerity.

noun

1. Careless headlong action: haste, hastiness, hurriedness, precipitance, precipitancy, precipitateness, precipitation, rush. See careful/careless.
2. Foolhardy boldness or disregard of danger: brashness, foolhardiness, incautiousness, recklessness, temerariousness, temerity. See careful/careless.

The noun has 2 meanings:

Meaning #1: the trait of acting rashly and without prudence
  Synonyms: heedlessness, mindlessness

Meaning #2: the trait of giving little thought to danger
  Synonyms: recklessness, foolhardiness