Name for “having no concern about the truthfulness of one’s own remarks”

Take the following statement:

I hate the ease with which X makes disparaging remarks about their rivals without the least concern as to whether they are truthful or fair.

Now I would like a word expressing this lack of concern, so that I could just plug it in the blank below and keep the meaning of the sentence above:

I hate the _________ with which X makes disparaging remarks about their rivals.

This is an all too common attitude and I think it deserves a name of its own. The word that came to my mind was levity, but I haven’t come across this word very often and I’m not sure of its particular tones and shades of meaning. Merriam-Webster defines levity as:

Simple definition
: a lack of seriousness
: an amusing quality
Full definition
1 : excessive or unseemly frivolity
2 : lack of steadiness: changeableness

The attitude I’m trying to name certainly displays lack of seriousness as to the truthfulness and fairness of the remarks, but I do not want to imply they are made in jest or that X is being silly or thoughtless. X could be very serious about their aims: “I’m going to say this; don’t give a dam whether that’s true or not; even if it’s not true I’ll get away with it.” This excludes, I think, all the words Merriam-Webster lists as related to levity, which probably means it excludes levity too:

facetiousness, flightiness, flippancy, frivolousness, frothiness, frivolity, light-headedness, light-mindedness, lightness, silliness

So I’ll accept an answer that despite my reservations shows that one of these words is indeed the one that works best in the sentence above; or gives a more fitting word; or shows that no word really fits (I am of course aware of the difficulties of proving a negative).

I prefer a single word but I’m willing to trade singleness for meaning: so I would take a short phrase it fits better than any single word.

Update

I’m spoilt for choice. But I wonder whether the various suggestions implying lack of concern would in my sentence imply lack of concern specifically for truth, which is what I’m after, or could instead be interpreted as lack of regard for norms of polite behaviour, rival’s feelings, or consequences (say, libel lawsuits, rivals reacting with violence, people feeling encouraged to attack the rivals, etc.)

Tweak the example sentence if it helps (say, I hate the ____ of X’s remarks).


Solution 1:

Consider the adjective cavalier

Showing arrogant or offhand disregard; dismissive: a cavalier attitude toward the suffering of others.

American Heritage Dictionary

While the noun, cavalierness is occasionally found, the adjectival use is much more common, often used in the phrase cavalier attitude.

The example given could be rephrased to use the adjective as follows

I hate the cavalier manner [or cavalier attitude] X displays in making disparaging remarks about their rivals

Solution 2:

What an opportunity to use a word everyone loves but never gets to use!

insouciance (ODO): showing a casual lack of concern; indifference.

And, as suggested by that definition, you have the synonym indifference.

Or, we can turn to those masters of ennui, the French, and offer blase and blithe, though for this use, the former smacks too much of jadednesses, for my taste, and on the other hand, the latter may be too chipper.

So, maybe a good compromise is the wholly unenthusiastic nonchalance.

Solution 3:

Someone who has no concern about the veracity of their remarks is certainly reckless and indulges in reckless speech.

  • Reckless speech comes with potential dangers. I doubt there are many people oblivious of the fact that freedom of speech is guaranteed by the First Amendment to the Constitution of the United States. The part of the Amendment that is specifically directed to our citizens, which is the focus of this article, says that “Congress shall make no law ... abridging freedom of speech.” This is to say that our government shall not constrain the speech of citizens willy-nilly. It is noteworthy that this First Amendment forbidding government abridgment of freedom of speech of citizens is not absolute. The Supreme Court of the United States’ interpretation delineates speeches that are not protected and those with limited protection.

  • These categories may include, but not limited to incitement, obscenity, false statements, speeches laden with fighting words, etc., which are unprotected; defamation, commercial speech, speech harmful to children, etc., which have limited protection. It is, therefore, no surprise that some of what we do or say directed at others may not be protected by the First Amendment.

  • reckless - adj -having or showing no regard for danger or consequences, heedless, rash. "recklessness" (noun)

Solution 4:

Jacinto, I submit to you the word casualness.

lack of interest or concern

"Her casualness distressed everyone who took the issue seriously."

"I hate the casualness with which X makes disparaging remarks about their rivals."

Or possibly aloofness.

at a distance

Finally, if you want to emphasise the cruelty of the lack of seriousness, you have callousness

not feeling or showing any concern about the problems or suffering of other people

"I hate the callousness with which X makes disparaging remarks about their rivals."