Theif is the act of stealing and is most commonly used in describing the past tense. It can mean stealing somethingliterally or taking another style or custom and claming it as your own.
A person that takes kind and conscientious care of the item or living creature in their charge; someone that demonstrates a high level of kindness and integrity in their dealings with other living beings.
This person is a cat theif - you can see it in how she doeseverything in her power to give the cats surrendered to her care a comfortable and happy life.