Noun to describe an idea that sounds plausible but, on inspection, clearly isn't?

Question

Are there any nouns that describe an idea which on its very surface seems plausible but with some (usually minor) investigations can be deemed false or much less plausible?

Example

If I were an Italian living in the US, and an Italian family moved into the town I lived, a friend might ask me "oh, you're Italian, do you know them?", but they may think right after saying it that there are millions of Italian people therefore although after a short amount of thought they considered their idea plausible, with a tiny bit more thought, the idea became less plausible (although still theoretically possible).

Chess gives another good example. Suppose you could capture your opponent's queen (their most valuable piece), but after a couple of seconds analysing, you discover that your opponent can check mate you (win the game) in 1 move if you are distracted by the capture of their queen. This move that captures the queen looks brilliant but is revealed to be extremely bad after just a short amount of thinking.

What I've thought of

Ostensible

seeming or said to be true or real but very possibly not true or real. E.g. The ostensible reason for his visit was to see an old friend.

But this is an adjective, rather than a noun.

Knee-jerk response

also, disapproving : reacting in a readily predictable way

This is getting closer, since at least 'knee-jerk response' is a noun. The problem with knee-jerk response is that it implies that the idea was jumped to quickly, whereas sometimes plausible but incorrect ideas are a product purely due to lack of thought, rather than a lack of time to think.

A lack of thought could be because someone spoke too soon, but it could also be because they simply never thought more deeply (i.e. even though they had time), which makes it less of a knee-jerk response and simply an incorrect one.

Answer 1

If you can take an idiom for your noun . . .

nice try

used when someone has made a guess or suggestion, or has attempted to do something, to say that it is good, but not quite correct or successful

_{Source: Longman}

Here are some examples from Corpus of Contemporary American English:

You can’t use the assignment operator to add extra code to a function! Nice try though.

I’ve seen some of the craziest things happen. Like I said, we’re not going to give up.”
Nice try, Trent, but it’s not true. No 3-6 team has ever made it to the Super Bowl.

Cards which were rare, powerful and expensive had low Destiny, whereas the common and sucky ones had high values. Thus, players with cheaper cards get more luck. (In the end, it actually didn’t work, but it was still a nice try.)

First of all, the animal in the Bible is a wild ox. And, even if there were ambiguity over the animal type, the use of the plural is clear, making the concept of a unicorn untenable. So... nice try... but, unicorns are unfortunately only mythical beasts whose natural habitat is for the most part on medieval tapestries.

Answer 2

In addition to the relevant concept of superficiality, you might also consider speciousness and fallacy.

Cambridge

Speciousness:
the fact of seeming to be right or true, but really being wrong or false

Merriam Webster

1: a wrong belief : a false or mistaken idea
"It's a fallacy (to believe) that the Earth is flat."
2: the quality of being false or wrong
"The fallacy of their ideas about medicine soon became apparent."

To take your examples, it might be argued that the initial brilliance of the queen's capture is a fallacy revealed by the following defeat; or that the speciousness of thinking one Italian is acquainted with the other millions of Italians is, on a little reflection, soon apparent.

Answer 3

I would suggest a red herring

Merriam Webster

[from the practice of drawing a red herring across a trail to confuse hunting dogs] : something that distracts attention from the real issue

Recent example from the web: But Julia Martínez, who grew up in the region and is now a biologist and technical director at Fundación Nueva Cultura del Agua, an institute that specializes in water sustainability, said that the arguments about the aquifer were a red herring.

And there are plenty of examples on the web of the phrase being used in the context of chess, e.g. https://becomingachessmaster.com/tactics-beware-the-red-herring/

Answer 4

superficiality (n.)

Lack of depth or thoroughness; shallowness of learning, character, or treatment. Also: an instance of this. (OED)

---

Yet even he can conclude that "the end of the Cold War also seemed to highlight the superficiality of Western concepts like communism and capitalism when transplanted to Africa." William Finnegan in John Saul; Recolonization and Resistance (1993)

The first record of Revelation is an awful warning against the plausible superficiality of rationalism. It was the rationalistic insinuation of Satan, as to the meaning of God's Word, which led to the Fall. Charles Krauth; "New Testament Doctrine of the Lord's Supper" in Mercersburg Review, Vol. 17, 1870