What do you call someone who thinks everyone is incompetent (doesn't know anything)?
I'm looking for a way to describe someone who thinks everyone is incompetent (that is, doesn't know anything) and always has to explain every minute (small) detail because his perception of the person's competence is that it's very low (thinking the person is not that smart).
If this person were here, he'd probably end this post with...
P.S. To answer the question go to the bottom of the page, type in the answer, and then hit submit. I should be able to see it relatively quickly.
How would you describe somebody like that?
The compulsive need to exolain everything in the minutest detail is contained in the rhetorical term Epexegesis
epexegesis (ɛˌpɛksɪˈdʒi:sɪs) (Collins) (plural) -ses (-,si:z) (rhetoric)
the addition of a phrase, clause, or sentence to a text to provide further explanation
the phrase, clause, or sentence added for this purpose
Example: ' his field or his male servant or his female servant, his ox or his donkey or anything that belongs to your neighbour' is an epexegesis of 'your neighbour's house (beth).'
Epexegetic, and epexegetical, are formed regularly. On the analogy of Athlete from Athletic, the perpetrator of obsessive explanation is an epexegete: (cf. 'exegete' n.)
epexegete (ɛˌpɛksɪˈdʒi:t) (hapaxlegomenon)
(noun) a person who provides minutely detailed explanation.
That doesn't cover the infantilizing attitude this person shows to those around; but it sort of describes the obsession that is so annoying.
infantilizing: treating someone as if that person were a child, with the result that they start behaving like one: (Cambridge online)
Now, a few years later (2021), 'mansplaining'would have to be included in a complete answer to this question. (Merriam Webster)
"Having to explain every minute detail" is not explicit in the definition of the word, but it is the sort of behavior you might expect from someone who
patronizes: speak to or behave toward someone as if they are stupid or not important
other people.
That particular meaning works with the verb form (patronize) and adjective form (patronizing). Patronizer is out there, but it seems to get more use for denoting someone who engages in the more pleasant sort of patronizing (sponsoring, supporting, or bringing trade to). If you're willing to accept a phrase rather than a single word, you could describe someone as a "patronizing overexplainer."
If you're just looking for an adjective, another suitable word is
haughty: having or showing the insulting attitude of people who think that they are better, smarter, or more important than other people
though its definition also lacks the specific detail of feeling the need to explain minutiae to others.
P.S. I included links for the questioner because common search engines apparently proved too difficult. Positioning the mouse cursor over the red letters in italics and left-clicking with the mouse will open the pages with the quoted definitions.
I can't think of a good phrase for this, but if you are looking for descriptors, the two that come to mind are condescending and belittling.
Though these don't specifically incorporate this person's perception of the lack of knowledge of those he is belittling, at least they describe the resulting behavior.
The first word that comes to mind is arrogant.
People who actively interfere with other people's jobs - typically because they don't think they're doing a good job - are commonly called micro-managers.
In the political arena, I'd call such a person intelligent, as activists are typically astounded by the almost unbelievable ignorance of the masses, which they often refer to as sheeple.
However, I'm going off on a tangent; it sounds like that's not the context you're looking at.