Translation:It tastes bad.
That's why I said I would accept it if I'm very lax. I'm also aware that 不味い can be used in different situations, for example, if you're in a bad situation and also to describe something of poor quality. I used the dictionary definition "unappetizing" because the examples given relating to まずい are related to food.
"Mazui" means "this is bad..." this is how you would most likely say "this is a bad situation" rather than using warui. (e.g. if someone has cornered you in combat)
i have heard "まずいだ" in different anime when someone has suddenly taken a bad situational hit in a combat situation.
(such as a critical artery getting damaged, critically wounded etc.)
this is how people would express their discontent in a serious situation when we would say something along the line of "!@#$ ***ing !!@#$" since there aren't really 'bad words' which exist in japanese.
My favorite anime Parasyte: The Maxim, which is a dark-psychological meaning of life anime contains this phrase a few times and i learned it without even knowing how to spell it.
this anime gets dark, so if you are depressed / suicidal, i highly recommend watching this before you die, it will help you understand reality first
Edit: 不味い can also mean "bad taste" or "distasteful" as other people said, so it's used in different ways. The form that i was describing is referring to a bad situation as "not to one's liking"
English sentences require a subject (generally) even if it's just a pronoun like it or this. Japanese can omit it, so the meaning in the sentence is basically 'is bad-tasting'.
That's no different to 'it is bad-tasting', there's no additional info carried by that it - both sentences need context for you to understand what the speaker is referring to. Japanese just lets you drop unnecessary words whereas English requires them (outside of informal speech anyway!)
AmaranthZi - です does not mean 'it'. It's a verb.
私は さむい です- I AM cold
あの犬は かわいいです - That dog over there IS cute
私たちは おそい です - We ARE late.
これらは りんご です - These ARE apples
Just a few examples. I've just gone back through and capitalised the part of the English sentence that is です.
やばい is a slang word and although I have never asked or looked up the meaning from personal experience and hearing how friends use it I would say that it comes close to meaning "Damn!" amongst other meanings. I remember I started using it after hearing a friend use it regularly and a friend from Eikaiwa told me that he thought I shouldn't use it, that it was slang and not particularly 'ladylike'. まずい on the other hand can mean something that literally tastes disgusting or something that is in bad taste - this could be in reference to clothing, a movie, a painting, something that makes you feel extremely uncomfortable or something that you think is abhorrent or off colour jokes.
taste bad is an incomplete sentence in English while the Japanese まずいです is complete.
これ would be better translated to "this", while これは means "speaking of this", and これはまずい means "speaking of this, it taste bad".
However, まずいです means "it tastes bad" (in a polite manner) where the "it" part is represented by the i-adjective まずい which already states the state of being by itself.
There are good translations and bad translations.
The word 不味い (まずい) has a meaning of "unappetizing" or "unpleasant", so the translation "It tastes bad" is closer than "it does not taste good."
"It does not taste good" would be おいしくない. This would be considered a politer response. むずい is pretty strong and potentially rude.