一牛 and 二B
yi nui ／ er B
俗语里用“牛”表示很强、厉害、了不起等
The first word: 一牛, means amazing/superb. However, the direct translation of the word means "one cow".
You usually use this as a compliment.
An example: "哇你太牛了“ (wa ni tai nui le) --> this means: Wow, you are too amazing!
用“二”形容一个人有点傻，不知所谓，行事不着边际之类的意思
The second word: 二B means silly but the direct translation of this word is "two B" which doesn't really make sense.
However, you may commonly see this online: 二B，二傻, which means that someone is calling the other as "you silly".
This is usually used in a joking way but it can also be quite rude to some people so use it cautiously!