Formal:
* Appropriate
* Copy (when used to describe stealing someone else's work)
* Embezzle (especially when referring to intellectual property)
* Misappropriate
* Purloin
* Steal
* Take (when used to describe stealing someone else's work)
Informal:
* Borrow (when used to describe taking someone else's work without permission)
* Lift
* Rip off
* Steal (informal use)
Other related terms:
* Counterfeit
* Forgery
* Imitate
* Pass off
* Pirate
It's important to note that some of these words have slightly different connotations. For example, "appropriate" implies a more formal or official taking, while "lift" is more informal and suggests a casual or quick taking.
The best synonym to use will depend on the specific context.