I was writing someone and was going to use the word “sinister” but I thought, to be careful, I should check the definition. I found this (part of the definition):
4 a : of, relating to, or situated to the left or on the left side of something
especially : being or relating to the side of a heraldic shield at the left of the person bearing it
b : of ill omen by reason of being on the left - SOURCE
What is “on the left” or “to the left?” I am not sure what that definition is telling me.
The use of the the word to mean “on the left” is usually used in reference to heraldry (as the definition you linked to notes), and simply means “on the left side” of the shield or coat of arms…but note that it seems to be from the point of view of the person bearing the shield, as per below:
The word’s origin is Latin, where it simply means “left.”
But why is that an “ill omen” as per:
“b : of ill omen by reason of being on the left”
As per this etymology article, it evolved into having a secondary, negative connotation, beyond simply “left”:
Heraldry? I was thinking of anatomy, like “ventriculus sinister” and “nervus vagus sinister”. I guess it depends on what one is into 
Yeah, heraldry. It’s bad enough the whole world is backward to us and we die sooner, but then we get this.
You clearly are not a lefty! I’m well aware of the original meanings for ‘sinister’. Also the origin of ‘gauche’.
Left-handedness being a synonym for either ‘clumsy’ or ‘somehow bad or having wrong intentions’ goes back aways.
Or, even in plain colloquial English, the phrase ‘left-handed complement’ 
And, meanwhile, the Latin word for “right” is “dexter,” from which English gets “dextrous.”
Good point!
Is that word origin maybe… where ‘Poindexter’ comes from, too? 
Just to add, without googling it, I think the term ‘Poindexter’ actually comes from an old ‘Felix the Cat’ cartoon or similar
But just to add again, the actual name ‘Poindexter’, upon which the term originated, is probably based on the root ‘Dexter’.
And yes, I may keep adding until the edit window closes just to see what I can get in under the wire…
Still in the edit window?
Looks like the answer is “kinda.”
Various links I’m finding say that “Poindexter” comes from Jerrais (a Romance language, traditionally spoken on the Channel Island of Jersey). In Jerrais, it was originally “Poingdestre,” which translates to “right fist.”
That’s some good research of the origin of the Poindexter family name.
Here’s the ‘Felix the Cat’ cartoon on YouTube that claims it’s the origin of using the name to apply to a ‘nerdy braniac’, which seems like the way I heard it. That’s just a little bit before my time, 1960 I think, but I thought the term (and the cartoon) dated back to the 30s.
Felix bowed in 1919 in his first silent iteration.
The character Poindexter is from the TV revival series, starting in 1958.
I’ve been called sinister my entire life, so don’t sweat it. It’s simply trivia.
And depending on how backwards the community or society, some lefties were forced into rightness. I
'm left handed and 64 yrs old and never had issues, but 20 years ago I had a left handed boss who had been forced to write as a righty when she was a kid. And my wife, also left handed, was told by her BS rural school teachers that left handedness was a “sign of the devil”.
Yeah, I never really had any bad experiences as a lefty in school, other than just having to adjust to righty scissors or whatever because the lone left-handed version was either broken or missing.
But I did hear secondhand, the bad, clumsy or evil connotations of being a lefty , for sure.
Haha, ‘secondhand’ sounds like a euphemism for ‘lefty’ itself.
My mom was left-handed and made to write with her right hand. Not to mention (so she says) no one made school desks for left-handed kids.
But, as an adult, this made her ambidextrous.
On eyeglass prescriptions, the two eyes are usually identified as “OD” and “OS”. OD = *oculus dexter" (Latin for “right eye”) and OS = “oculus sinister” (“left eye”). I think Oculus Sinister would be a great name for a supervillian.
I see that the OED has its first quotation for “poindexter” meaning “an overly diligent student” in 1981, but that seems unlikely to be the earliest usage.
Simon Bar Sinister was, in fact, one of the main villains in the 1960s “Underdog” cartoons.
“Bar Sinister” is a heraldic term, referring to a diagonal line, and which is usually associated with a bastard son.
As a left-handed writer who was free to be me, I wonder how many great writers were squandered by the insistence that they write right-handed. (Or painters? It’s kind of hard to show off your talent with your non-dominant hand.) It makes me sad to think about.
What boggles my mind is the variety of treatment at the same time in history, depending on where someone was raised.
I started school (kindergarten) in 1964 and, give or take a year or two, my wife and my former boss. I started in a suburb of Montreal for two years and did the rest of my school in Ottawa.
And as you said , Spice_Weasel, I was free to be me - my handedness was as noteworthy as eye or hair colour; completely irrelevant and seamless. My wife and former boss, however, had totally different and stupid experiences. My boss was a right handed writer with atrocious hand-writing.
Interestingly, a lot of my profession (Instructional Systems Designers) are lefties.