A more thorough explanation:

Definition: An act or person characterized by theft.

Examples:

• He was caught in the act of theftuous behavior when he stole the wallet from the unsuspecting victim.
• The store owner suspected the theftuous employee of stealing merchandise from the store.

These examples illustrate the definition of theftuous by showing how an act or person can be characterized by theft. In the first example, the person is caught in the act of stealing, which is a clear example of theftuous behavior. In the second example, the store owner suspects the employee of stealing, which is another example of theftuous behavior.