If one thing is dissimilar to another, or if two things are dissimilar, they are very different from each other.
His methods were not dissimilar to those used by Freud.
他用的方法和弗洛伊德用的没有什么不同。
It would be difficult to find two men who were more dissimilar.
要找出两个更不同的人来可不容易。