What does his arms sliced through the water like a hot knife through butter mean

Question

The metaphor makes no sense to me and I need  a lot of help

Answer 1

Metaphors are comparing so you separate the sentence into (his arms sliced through the water) and (a hot knife through butter) by doing so you can look at the second part and try to visualize what is said. a hot knife can easily slice through butter. meaning that "his arm" easily cut/moved through the water. did that help?? good luck!