What is a noun for egregious?

There isn't a single perfect noun equivalent for "egregious." However, depending on the context, these nouns might capture similar meanings:

For an egregious act:

* Outrage

* Abomination

* atrocity

* offense

* transgression

* misconduct

* infraction

* breach

For an egregious mistake:

* Blunder

* Fiasco

* Error

* Miscalculation

For an egregious display of something negative:

* Excess

* Extremity

* Outlandishness

* Absurdity

Ultimately, the best noun to use will depend on the specific context of what is being described as "egregious."