kitten：一般用来称呼一岁以下的小猫
I was given a kitten for my birthday. 我的生日，别人送了我一只小猫咪。

kitty：<口>凡事是猫，不分年龄大小都可以称作kitty
Kitty, kitty, where are you?

moggy/moggie：指长相普通，没有什么特别出众的地方，有时候甚至可能还有点邋遢的猫
The moggy next door has just had a litter of six kittens. 隔壁邻居家的猫刚刚生了六只小猫。

mouser：能抓老鼠的猫
Sammy is a good mouser. We don't have any mice problem at home.
Sammy是一个捕鼠能手。我们家里没有老鼠。

pussycat：对小猫的昵称；用来幽默地形容某人“热别温柔，像小姑娘一样”
Where are you, pussycat?
你在哪里啊？小猫咪？
George looks tough, but he's a pussycat really.
George看着很厉害，其实是个......娘炮！