What do you call people who think they're always right?
3rd vote for "know-it-all" as an all-purpose term that can be used somewhat politely.
In addition to answers above, "smart ass" and "wise ass" are more vulgar, but quite common.
The more polite alternatives are "smart-aleck" and (the rather outdated) "wise-acre" (or "wiseguy" which can also be slang for a joker or a mafia member ... depends on context).
A "pedant" is someone who makes a point of correcting others and showing off how much they know.
Also, whatever my wife & coworkers decide to call me that day... ;)
If someone thinks that they are always right, then they are wrong, for someone who is always right is infallible and certainly I have never come across or heard of anyone in history who has been such. Infallibility has, of course, been claimed as an attribute of the Pope but in recent years it is my understanding that even that personage has not tended to claim such an attribute.
Most respondents and the questioner seem to understand this question to refer to a person who claims, asserts or believes themselves to be right all of the time, even though they are not. There are many words, some of them already given, that express the manner in which others might see a person who makes such a claim: opinionated is perhaps the best I've seen, though even that falls short for someone can be opinionated about some things but accept their lack of knowledge or mistaken thought about others.
Leaving aside the derogatory terms such as, know-it-all the purpose of which is to deride rather than define, and seeking only to define the characteristic of a belief by someone that they are "always right" suggests that although words such as delusional, foolish, misguided etc. certainly may be appropriate to the description of someone who believe they are always right, they may, as readily apply to someone who doesn't have that delusion but who demonstrates behaviours or characteristics that befit the use of the particular adjective.
Try as I might, therefore, I have been unable to find any single word in the English Language which specifically defines a person's belief that they are always right. My conclusion is thus that, as infallibility defines "never being wrong" and as delusional defines having an unrealistic belief, then an appropriate term for a person who believes that they are always right is: delusionally infallible.
Adjective, definition: inclined to lay down principles as incontrovertibly true. "he gives his opinion without trying to be dogmatic"
synonyms: opinionated, peremptory, assertive, insistent, emphatic, adamant, doctrinaire, authoritarian, imperious, dictatorial, uncompromising, unyielding, inflexible, rigid...
In life we make choices all day long which influence how we act, how we think and how we interpret and view our world....Of course, we all believe we have made all the correct choices... because if we didn't then we wouldn't have made them.. Being "dogmatically assertive" is one of the three primary motives (how we think, act and respond to stimuli) of a human. The other two primary motives are desire for property and desire for personal pleasure. However none is as dominant as being assertive.
pompous - affectedly and irritatingly grand, solemn, or self-important.
pretentious - attempting to impress by affecting greater importance, talent, culture, etc., than is actually possessed.
condescending - having or showing a feeling of patronizing superiority.
Source: Oxford online dictionary
I can't find the right word either. Narcissist is almost there but I think they are more delusional with the idea of themselves.
I know someone who I call an absolutist (absolutism). Not sure if it works as a person. And most references to the -ism are political in nature. But. This person (which I love) is absolutely right every argument and preachy and very crafty at sculpting the conversation back on to me for being too young or not listening well enough . It drives me nuts. She is terribly smart but not reflective on herself like she is with the world around her.
People that think they are always right are normal. People don't function well when thinking they are wrong. And if they think they are wrong and tell you, we call those people liars. If they think they're right and they are not we call those people mistaken, if they think they are right and they are we call those people correct.
When you are right you are right without status. What I will accept is that the person is highly opinionated and thinks the same of themselves. To say they are less you would have to prove them wrong and subject yourself to a private court matter.
I think you're talking about a Narcissist
narcissist: a person who admires himself or herself too much, especially their appearance
A person who admires himself too much think that they are always right.