I'm sure you're already aware that a cat is a grown up kitten, or any other member of the Felis family, such as a lion or tiger (often referred to as big cats). The term cat can also be applied to members of other species which have a catlike appearance.
If a person is described as a cat they'll almost certainly be female and definitely malicious or spiteful. To be catty is to behave as this kind of cat, not the furry four-legged version.
At one time I had a day job in which I used a cat. A cat-o'-nine-tails that is. This was a rope whip, used historically to punish sailors. It got its name from the nine knotted tails and the belief that cats have nine lives. I was gentle when I demonstrated. Well gentle-ish! (These cats were carried in bags – you didn't want to be around when the cat was let out of the bag.)
If you're a cat's paw then you're someone who is used by another, a cat burglar enters a building by climbing up to a window, balcony or roof and a cat and dog relationship is an argumentative one.
A person or thing described as the cat's whiskers or cat's pyjamas will be excellent in some way.
Here's a free to enter competition to win a three book deal with Choc Lit Publishing. The entry must feature a cat in some way. The snag is you only have until the end of next month to enter – now that's put the cat among the pigeons!
There are other phrases containing the word cat – can you think of any?