Translation:It is neither a dog nor a cat.
He did not ask about the phrase "it is not dog". Please read what people are asking about. Also this forum is for speakers of English, so telling people in here that something is not valid English is at best distasteful. By the way, "It is neither dog nor cat" is perfectly valid English. I say this in case there are others in here who are also trying to learn some English.
To say it is neither a dog nor a cat is a very awkward translation as some comments show" is it a pig" so how would this sentence be applied. I think in a situation where blame was being vent and i knew neither dog nor cat were at fault" It's neither the dog (n)or the cat. But I am marked wrong.