What action characterizes shoplifting by concealing merchandise?

Concealing items with intent to steal distinctly characterizes shoplifting by focusing on the act of hiding merchandise with the purpose of theft. This behavior indicates a clear intention to take the items without paying for them. Concealment is a key component of shoplifting, as it demonstrates the individual's awareness that they are acting unlawfully and deliberately attempting to evade detection.

In the context of the other options, while taking items off the shelf, using fake identification, or purchasing items with stolen money may involve dishonest actions, they do not specifically illustrate the act of concealing merchandise with the objective of theft, which is central to the definition of shoplifting. Thus, option C effectively captures the essence of shoplifting behavior.