I have written "That is not a furniture". Unfortunately It was not correct. What is the real sense of furniture and how this word is used in English ?
"Furniture" in English never takes an indefinite article. Possibly because it is a concept rather than a thing.
You were right. They got it wrong. Quite a number of mistakes other commented, too.
When no and when not? I dont understand. Im hungarian. That is no furniture. Is no good?
"Not" is used as an adverb, negating a verb (~nem); and "no" is used as an adjective, negating a noun (~semmilyen). Both can work in this sentence.
My translation, 'It is not furniture', was marked incorrect.
So if 'Az nem bútor' is only 'That is not furniture', how could one say 'It is not furniture'?