What's a word that means a common saying which is arguably untrue?
Such as "money can't buy happiness" or "what doesn't kill you makes you stronger". Generally a false adage or something like that. All I could think of was "fallacious bumper sticker" which just sounds stupid.
Usually said to convince someone that you should be there to help family regardless of what that family did to you. Unfortunately the full saying is "The blood of the covenant is thicker than the water of the womb", meaning the ties you form with friends can be stronger than the family you you born into.
This is probably not true. The concept of this phrase but referring to family is probably a modern confusion. There is no clear evidence it means it was really referencing ties to friends. Although I wish it did. Here's some further reading from others also looking for a clearer reference.
Most of those old sayings have had the rejoinder omitted, which completely shifted their original meaning, in fact. For example, "Great minds think alike" originally closed with "but rarely do they differ", etc.
"Fallacy" works. These are also adages, clichés, platitudes and folk wisdom, but neither really means "falsehood" per se. However, many of them just rationalize whatever: the money one is factually incorrect and exemplifies "sour grapes", silver linings is not a bad idea but also not necessarily true, any number of things will not kill you but make you wish they had, etc.
Whoever came up with the "What doesn't kill you makes you stronger" adage never met a person with locked-in syndrome. That's where you're totally paralyzed but also totally conscious. There have been patients where the doctors thought they were in a persistent coma, but they were actually going crazy trapped in their own skulls.
These fall under the category of "Half-baked Idea". This includes any idea that obviously hasn't been thought all the way through. Half-baked ideas can range from the absurd (e.g. "The Earth is flat."), to the benignly optimistic (e.g. "Everything works out for the best.")
For example someone says "you can't teach an old dog new tricks" and you might say "that's a questionable phrase." or "I doubt the validity of that platitude". But is there something specific to label it as, i.e. "That's a [insert word]"
It annoys me that people keep saying "figuratively" is what they mean instead of "literally". "Figuratively" may be the opposite, and technically correct, but the use of the word "literally" in this way is to strengthen a statement. A more appropriate correction would be "actually" or "seriously", which holds the intended meaning. "Figuratively" is the last thing it should be replaced with.
Yep decimate is so commonly misused that our lovely descriptivist dictionaries are now incorporating the incorrect use as correct. It’s too bad, too, because the word had a very specific meaning which is now lost. The language is less useful for changes like this.
Others have said "canard" which is almost certainly the best term; and "old wives' tale" which is the same but for an anecdote or advice rather than pithy saying.
I think "aphorism" also fits the bill for a proverb if dubious legitimacy.
Maybe a "specious claim" or "folk wisdom" or "empty rhetoric"?
The word I would normally gravitate to is a "truism", however that's not really used to describe something that is necessarily false... just something that sounds insightful, but doesn't have any meaningful depth (e.g. "every cloud has a silver lining").