n'importe quoi
I am trying to understand n'importe quoi. I keep hearing French speakers say it but it is quite difficult to understand the meaning because it seems to depend on the context.
I believe it is used in the following situations:

Je fais n'importe quoi = I am messing about, similar to je déconne.
Il dit n'importe quoi = He is talking rubbish

If someone tells you something which seems quite farfetched, you could reply by saying N'importe quoi meaning 'Yeah right/ Whatever'.

Please tell me if what I have proposed is correct and also if there are any other situations in which you can use n'importe quoi, n'importe qui, n'importe où

Thanks

Question

n'importe quoi
I am trying to understand n'importe quoi. I keep hearing French speakers say it but it is quite difficult to understand the meaning because it seems to depend on the context. 
I believe it is used in the following situations:

Je fais n'importe quoi = I am messing about, similar to je déconne.
Il dit n'importe quoi = He is talking rubbish

If someone tells you something which seems quite farfetched, you could reply by saying N'importe quoi meaning 'Yeah right/ Whatever'.

Please tell me if what I have proposed is correct and also if there are any other situations in which you can use n'importe quoi, n'importe qui, n'importe où

Thanks

Answer

Yes, but I would explain it as meaning "anything" and "nothing" rolled into one.

ex : je ferais n'importe quoi pour elle - I would do anything for her

Think about the sentence you wrote (Il dit n'importe quoi) it does mean he's talking nonsence, but it litterally means "he says anything that come into his mind, which is frankly not related to the current discussion."

And that other one (Je fais n'importe quoi) yes it does mean I am messing about but it litterally means "I'm doing nothing of particular interest/nothing useful"

Answer

Yes, the meaning is correct. If someone were to tell me something which seems quite farfetched, I would make a complete sentence and say either "C'est n'importe quoi" or "C'est du n'importe quoi".

Answer

A good translation of: N'importe quoi if used by itself would be bullshit.

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