Contemporary equivalent of the word “moxie” as defined herein

Question

I'm fiddling around with a piece of prose that my other half once wrote, trying to get it translated to English.

The text is basically an inner monologue. After a burst of (verbal) aggressiveness, the "inner" speaker gradually gets hold of himself/herself, and despite the fairly reasonable content of what has been said, he/she is left with a certain sense of remorse due to the severeness of his/her manners.

At that point he/she says something like:

-A stupid grit is all that's left...

Now, that was just my very first attempt to render the sentence; but I know that grit [courage and resolve; strength of character (Oxford D.)] isn't quite the word I'm looking for. It's just familiar enough to be used without noticeable hesitation.

I asked a reliable elder for a piece of cyber-advice and he recommended foolish bravado.

I objected, saying that "bravado" gives me the impression of a slightly masculine word, whereas I'm looking for something unisex, so to speak. Eventually I got convinced my impression was wrong, but "bravado" still sounds a bit "cowboy" in my (European) ears, probably due to its phonetic resemblance to Rio Bravo and its overall Spanish/Mexican features.

For now, I've changed grit to chutzpah, meaning "extreme self-confidence or audacity" (again, according to Oxford D.).

But whereas grit was a bit too close to courage (which can hardly be a bad thing), chutzpah seems to be at the other end of the spectrum, connoting excessiveness (which is rarely a good thing).

I felt I'd like something more ambiguous. So I eventually stumbled upon this word:

mox·ie (mŏk′sē)
n. Slang
1. The ability to face difficulty with spirit and courage.
2. Aggressive energy; initiative:
3. Skill; know-how.

Macmillan is more concise about it: energy, confidence, and determination. It does however tell you that apart from being slang, the word is also old-fashioned.

And I wouldn't want to use outdated language.

The triplet of possible interpretations does, however, serve my intentions perfectly, aggressive energy (2) being a potential downside of an overall courageous character...

Thus comes my question: what would be an accurate modern equivalent of the word moxie, able to connote all three aforementioned aspects of someone's personality?

And I'm not looking for anything offensive, like b@ll$ or whatever. Just a pertinent word one might hear "on the street", with a fair share of potential to fit in this sentence:

A stupid ***** is all that's left.
(kinda muttered in a state of confusion; a stalemate between pride and remorse).

Answer 1

A stupid feistiness is all that is left. Feistiness is the state of being feisty, which is defined in the Cambridge English Dictionary as:

active, forceful and determined; Example: She’s a feisty kid who is not afraid to challenge authority

The Oxford Living Dictionaries says in its first definition that feistiness is typically used for someone relatively small:

1. (of a person, typically one who is relatively small) lively, determined, and courageous: ‘a love story with a feisty heroine who's more than a pretty face’

1.1. Touchy and aggressive:

‘he got a bit feisty and tried to hit me’

Feisty people are often punching above their weight, and can be successful doing so, particularly if they have good judgment. Your character sounds as though he/she is struggling with the consequences of a lapse of judgment.