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What is the difference between the subject words?

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One's a noun, the other's an adjective? :P – Noldorin Nov 14 '10 at 21:10
up vote 1 down vote accepted

Compare the examples:

1. Idiot (noun) vs. stupid (noun)

Only an idiot would invest in the company back in the 90's.

Idiot = a person affected with extreme mental retardation (offensive).

He was a genius at math, but a total stupid when it came to women.

Total stupid = antonym of genius.

2. Stupid (adjective)

That was a stupid idea!

Note: Idiot can't be used as an adjective. Idiotic is the adjective. For idiotic (adjective) vs. stupid (adjective), refer to Claudiu's answer.

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I think in your note you meant to either say " Idiot can't be used as an adjective" or " stupid can't be used as a noun". – Kosmonaut Nov 14 '10 at 21:28
@Kosmonaut, thanks, I just edited the note. – b.roth Nov 14 '10 at 21:33
While "stupid" is technically a noun, using it as above is highly non-idiomatic for American English. – res Nov 15 '10 at 15:42
@res: similarly non-idiomatic for British English. I haven't ever heard it used other than as an adjective. – Joe Kearney Nov 25 '10 at 13:20

Idiot is a noun. Stupid is an adjective. So let's compare the same parts of speech... Note: this is all just my opinion, so we'll see based on the number of upvotes whether other people use the words the same way.

idiot vs. stupid person

  • a stupid person is just somebody who isn't very smart or intellectual. It's not their fault. It's same as saying "he's a bit slow." You could have a person who is hard-working but stupid, for example.
  • An idiot, on the other hand, is worse. It means someone who does idiotic/stupid things, like having friends shoot fireworks into their face. It's more of a behavior thing. Someone can be intelligent but purposefully (or subconsciously) act like an idiot all the time.

idiotic vs. stupid

These are more similar in meaning. They just describe things or situations where, for example, unfavorable things happen for avoidable reasons, or when something doesn't work out, example: "Having that meeting was a stupid idea."

In this case, I think idiotic just means stupid, but to a higher degree. If having the meeting was a stupid idea, then it was just a waste of time and nothing got done. If having the meeting was an idiotic idea, then perhaps the result was starting a war or someone getting killed.

Other adjectives meaning stupid/idiotic: retarded, moronic, dumb.

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Claudiu, note that stupid can also be a noun. For example, "he was a genius at math, but a total stupid when it came to women". – b.roth Nov 14 '10 at 21:12
ah true. it sounds a bit silly though. "He is such a stupid". i think the question asker meant the more commonly-used one, the adjective. – Claudiu Nov 14 '10 at 21:50
Using stupid as a noun does make one sound a bit stupid... – Benjol Nov 16 '10 at 8:53

The current meanings aside for a second, I heard that 'Idiot' along with 'Moron' and 'Imbecile' were used as tachnical classifications of mental retardation by Henry Goddard's and that all these terms seeped into general usage as different ways of saying stupid.

Wikipedia for instance says "The term 'idiot' was used to refer to people having an IQ below 30"

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protected by tchrist Jul 2 '14 at 2:49

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